diff --git a/debug.log b/debug.log
new file mode 100644
index 000000000000..3e3495567796
--- /dev/null
+++ b/debug.log
@@ -0,0 +1 @@
+[0829/202002.254:ERROR:crashpad_client_win.cc(868)] not connected
diff --git a/src/lake/Lake/CLI/Help.lean b/src/lake/Lake/CLI/Help.lean
index 5bc0902d57c1..af988757a565 100644
--- a/src/lake/Lake/CLI/Help.lean
+++ b/src/lake/Lake/CLI/Help.lean
@@ -18,6 +18,7 @@ COMMANDS:
   init <name> <temp>    create a Lean package in the current directory
   build <targets>...    build targets
   exe <exe> <args>...   build an exe and run it in Lake's environment
+  check-build           check if any default build targets are configured
   test                  test the package using the configured test driver
   check-test            check if there is a properly configured test driver
   lint                  lint the package using the configured lint driver
@@ -126,6 +127,19 @@ TARGET EXAMPLES:        build the ...
 A bare `lake build` command will build the default facet of the root package.
 Package dependencies are not updated during a build."
 
+def helpCheckBuild :=
+"Check if any default build targets are configured
+
+USAGE:
+  lake check-build
+
+Exits with code 0 if the workspace's root package has any
+default targets configured. Errors (with code 1) otherwise.
+
+Does NOT verify that the configured default targets are valid.
+It merely verifies that some are specified.
+"
+
 def helpUpdate :=
 "Update dependencies and save them to the manifest
 
@@ -375,6 +389,7 @@ def help : (cmd : String) → String
 | "new"                 => helpNew
 | "init"                => helpInit
 | "build"               => helpBuild
+| "check-build"         => helpCheckBuild
 | "update" | "upgrade"  => helpUpdate
 | "pack"                => helpPack
 | "unpack"              => helpUnpack
diff --git a/src/lake/Lake/CLI/Init.lean b/src/lake/Lake/CLI/Init.lean
index 5ee656e089cd..cce91653967d 100644
--- a/src/lake/Lake/CLI/Init.lean
+++ b/src/lake/Lake/CLI/Init.lean
@@ -52,7 +52,7 @@ s!"import Lake
 open Lake DSL
 
 package {repr pkgName} where
-  -- add package configuration options here
+  version := v!\"0.1.0\"
 
 lean_lib {libRoot} where
   -- add library configuration options here
@@ -64,6 +64,7 @@ lean_exe {repr exeName} where
 
 def stdTomlConfigFileContents (pkgName libRoot exeName : String) :=
 s!"name = {repr pkgName}
+version = \"0.1.0\"
 defaultTargets = [{repr exeName}]
 
 [[lean_lib]]
@@ -79,7 +80,7 @@ s!"import Lake
 open Lake DSL
 
 package {repr pkgName} where
-  -- add package configuration options here
+  version := v!\"0.1.0\"
 
 @[default_target]
 lean_exe {repr exeName} where
@@ -88,6 +89,7 @@ lean_exe {repr exeName} where
 
 def exeTomlConfigFileContents (pkgName exeName : String) :=
 s!"name = {repr pkgName}
+version = \"0.1.0\"
 defaultTargets = [{repr exeName}]
 
 [[lean_exe]]
@@ -100,7 +102,7 @@ s!"import Lake
 open Lake DSL
 
 package {repr pkgName} where
-  -- add package configuration options here
+  version := v!\"0.1.0\"
 
 @[default_target]
 lean_lib {libRoot} where
@@ -109,6 +111,7 @@ lean_lib {libRoot} where
 
 def libTomlConfigFileContents (pkgName libRoot : String) :=
 s!"name = {repr pkgName}
+version = \"0.1.0\"
 defaultTargets = [{repr libRoot}]
 
 [[lean_lib]]
@@ -120,11 +123,11 @@ s!"import Lake
 open Lake DSL
 
 package {repr pkgName} where
-  -- Settings applied to both builds and interactive editing
+  version := v!\"0.1.0\"
+  keywords := #[\"math\"]
   leanOptions := #[
     ⟨`pp.unicode.fun, true⟩ -- pretty-prints `fun a ↦ b`
   ]
-  -- add any additional package configuration options here
 
 require \"leanprover-community\" / \"mathlib\"
 
@@ -135,6 +138,8 @@ lean_lib {libRoot} where
 
 def mathTomlConfigFileContents (pkgName libRoot : String) :=
 s!"name = {repr pkgName}
+version = \"0.1.0\"
+keywords = [\"math\"]
 defaultTargets = [{repr libRoot}]
 
 [leanOptions]
diff --git a/src/lake/Lake/CLI/Main.lean b/src/lake/Lake/CLI/Main.lean
index 8e3b3df4f1c1..477951c30263 100644
--- a/src/lake/Lake/CLI/Main.lean
+++ b/src/lake/Lake/CLI/Main.lean
@@ -316,6 +316,11 @@ protected def build : CliM PUnit := do
   if showProgress then
     IO.println "Build completed successfully."
 
+protected def checkBuild : CliM PUnit := do
+  processOptions lakeOption
+  let pkg ← loadPackage (← mkLoadConfig (← getThe LakeOptions))
+  noArgsRem do exit <| if pkg.defaultTargets.isEmpty then 1 else 0
+
 protected def resolveDeps : CliM PUnit := do
   processOptions lakeOption
   let opts ← getThe LakeOptions
@@ -478,6 +483,66 @@ protected def translateConfig : CliM PUnit := do
   if outFile?.isNone then
     IO.FS.rename pkg.configFile (pkg.configFile.addExtension "bak")
 
+def ReservoirConfig.currentSchemaVersion : StdVer := v!"1.0.0"
+
+structure ReservoirConfig where
+  name : String
+  version : StdVer
+  versionTags : List String
+  description : String
+  keywords : Array String
+  homepage : String
+  platformIndependent : Option Bool
+  license : String
+  licenseFiles : Array FilePath
+  readmeFile : Option FilePath
+  doIndex : Bool
+  schemaVersion := ReservoirConfig.currentSchemaVersion
+  deriving Lean.ToJson
+
+protected def reservoirConfig : CliM PUnit := do
+  processOptions lakeOption
+  let opts ← getThe LakeOptions
+  let cfg ← mkLoadConfig opts
+  let _ ← id do
+    let some verStr ← takeArg?
+      | return ReservoirConfig.currentSchemaVersion
+    match StdVer.parse verStr with
+    | .ok ver => return ver
+    | .error e => error s!"invalid target version: {e}"
+  noArgsRem do
+  let pkg ← loadPackage cfg
+  let repoTags ← GitRepo.getTags pkg.dir
+  let licenseFiles ← pkg.licenseFiles.filterMapM fun relPath => do
+    return if (← (pkg.dir / relPath).pathExists) then some relPath else none
+  let readmeFile :=
+    if (← pkg.readmeFile.pathExists) then some pkg.relReadmeFile else none
+  let cfg : ReservoirConfig := {
+    name := pkg.name.toString
+    version := pkg.version
+    versionTags := repoTags.filter pkg.versionTags.matches
+    description := pkg.description
+    homepage := pkg.homepage
+    keywords := pkg.keywords
+    platformIndependent := pkg.platformIndependent
+    license := pkg.license
+    licenseFiles := licenseFiles
+    readmeFile := readmeFile
+    doIndex := pkg.reservoir
+  }
+  IO.println (toJson cfg).pretty
+
+protected def versionTags : CliM PUnit := do
+  processOptions lakeOption
+  let opts ← getThe LakeOptions
+  let cfg ← mkLoadConfig opts
+  noArgsRem do
+  let pkg ← loadPackage cfg
+  let tags ← GitRepo.getTags pkg.dir
+  for tag in tags do
+    if pkg.versionTags.matches tag then
+      IO.println tag
+
 protected def selfCheck : CliM PUnit := do
   processOptions lakeOption
   noArgsRem do verifyInstall (← getThe LakeOptions)
@@ -491,6 +556,7 @@ def lakeCli : (cmd : String) → CliM PUnit
 | "new"                 => lake.new
 | "init"                => lake.init
 | "build"               => lake.build
+| "check-build"         => lake.checkBuild
 | "update" | "upgrade"  => lake.update
 | "resolve-deps"        => lake.resolveDeps
 | "pack"                => lake.pack
@@ -510,6 +576,8 @@ def lakeCli : (cmd : String) → CliM PUnit
 | "exe" | "exec"        => lake.exe
 | "lean"                => lake.lean
 | "translate-config"    => lake.translateConfig
+| "reservoir-config"    => lake.reservoirConfig
+| "version-tags"        => lake.versionTags
 | "self-check"          => lake.selfCheck
 | "help"                => lake.help
 | cmd                   => throw <| CliError.unknownCommand cmd
diff --git a/src/lake/Lake/CLI/Translate/Lean.lean b/src/lake/Lake/CLI/Translate/Lean.lean
index 2f2ddc657418..a18d6426df70 100644
--- a/src/lake/Lake/CLI/Translate/Lean.lean
+++ b/src/lake/Lake/CLI/Translate/Lean.lean
@@ -20,6 +20,9 @@ open DSL System Lean Syntax Parser Module
 private local instance : Quote FilePath where
   quote path := quote path.toString
 
+private local instance [Quote α] : Quote (Array α) where
+  quote xs := let xs : Array Term := xs.map quote; Unhygienic.run `(#[$xs,*])
+
 private local instance : BEq FilePath where
   beq a b := a.normalize == b.normalize
 
@@ -67,6 +70,13 @@ def quoteLeanOption (opt : LeanOption) : Term := Unhygienic.run do
 
 private local instance : Quote LeanOption := ⟨quoteLeanOption⟩
 
+protected def LeanVer.quote (v : LeanVer) : Term := Unhygienic.run do
+  let lit := Syntax.mkLit interpolatedStrLitKind  v.toString.quote
+  let stx := mkNode interpolatedStrKind #[lit]
+  `(v!$stx)
+
+private local instance : Quote LeanVer := ⟨LeanVer.quote⟩
+
 /-! ## Configuration Encoders -/
 
 def WorkspaceConfig.addDeclFields (cfg : WorkspaceConfig) (fs : Array DeclField) : Array DeclField :=
@@ -91,7 +101,8 @@ def LeanConfig.addDeclFields (cfg : LeanConfig) (fs : Array DeclField) : Array D
 
 def PackageConfig.mkSyntax (cfg : PackageConfig)
   (testDriver := cfg.testDriver) (lintDriver := cfg.lintDriver)
-  : PackageDecl := Unhygienic.run do
+: PackageDecl := Unhygienic.run do
+  have : Quote Term := ⟨id⟩
   let declVal? := mkDeclValWhere? <| Array.empty
     |> addDeclFieldD `precompileModules cfg.precompileModules false
     |> addDeclFieldD `moreGlobalServerArgs cfg.moreGlobalServerArgs #[]
@@ -108,9 +119,26 @@ def PackageConfig.mkSyntax (cfg : PackageConfig)
     |> addDeclFieldD `testDriverArgs cfg.testDriverArgs #[]
     |> addDeclFieldD `lintDriver lintDriver ""
     |> addDeclFieldD `lintDriverArgs cfg.lintDriverArgs #[]
+    |> addDeclFieldD `version cfg.version v!"0.0.0"
+    |> addDeclField? `versionTags (quoteVerTags? cfg.versionTags)
+    |> addDeclFieldD `description cfg.description ""
+    |> addDeclFieldD `keywords cfg.keywords #[]
+    |> addDeclFieldD `homepage cfg.homepage ""
+    |> addDeclFieldD `license cfg.license ""
+    |> addDeclFieldD `licenseFiles cfg.licenseFiles #["LICENSE"]
+    |> addDeclFieldD `readmeFile cfg.readmeFile "README.md"
+    |> addDeclFieldD `reservoir cfg.reservoir true
     |> cfg.toWorkspaceConfig.addDeclFields
     |> cfg.toLeanConfig.addDeclFields
   `(packageDecl|package $(mkIdent cfg.name):ident $[$declVal?]?)
+  where
+    quoteVerTags? (pat : StrPat) : Option Term :=
+      match pat with
+      | .mem xs => if xs.isEmpty then Unhygienic.run `(∅) else some (quote xs)
+      | .startsWith pre => Unhygienic.run `(.$(mkIdent `startsWith) $(quote pre))
+      | .satisfies _ n =>
+        if n.isAnonymous || n == `default then none else
+        Unhygienic.run `(.$(mkIdent n))
 
 private def getEscapedNameParts? (acc : List String) : Name → Option (List String)
   | Name.anonymous => if acc.isEmpty then none else some acc
diff --git a/src/lake/Lake/CLI/Translate/Toml.lean b/src/lake/Lake/CLI/Translate/Toml.lean
index c35fe583bf8d..8a7bc9a55764 100644
--- a/src/lake/Lake/CLI/Translate/Toml.lean
+++ b/src/lake/Lake/CLI/Translate/Toml.lean
@@ -61,6 +61,7 @@ def LeanConfig.toToml (cfg : LeanConfig) (t : Table := {}) : Table :=
   |>.smartInsert `weakLinkArgs cfg.weakLinkArgs
 
 instance : ToToml LeanConfig := ⟨(toToml ·.toToml)⟩
+instance : ToToml LeanVer := ⟨(toToml <| toString ·)⟩
 
 protected def PackageConfig.toToml (cfg : PackageConfig) (t : Table := {}) : Table :=
   t.insert `name cfg.name
@@ -75,8 +76,25 @@ protected def PackageConfig.toToml (cfg : PackageConfig) (t : Table := {}) : Tab
   |>.smartInsert `releaseRepo (cfg.releaseRepo <|> cfg.releaseRepo?)
   |>.insertD `buildArchive (cfg.buildArchive?.getD cfg.buildArchive) (defaultBuildArchive cfg.name)
   |>.insertD `preferReleaseBuild cfg.preferReleaseBuild false
+  |>.insertD `version cfg.version v!"0.0.0"
+  |> smartInsertVerTags cfg.versionTags
+  |>.smartInsert `keywords cfg.description
+  |>.smartInsert `keywords cfg.keywords
+  |>.smartInsert `homepage cfg.homepage
+  |>.smartInsert `license cfg.license
+  |>.insertD `licenseFiles cfg.licenseFiles #["LICENSE"]
+  |>.insertD `readmeFile cfg.readmeFile "README.md"
+  |>.insertD `reservoir cfg.reservoir true
   |> cfg.toWorkspaceConfig.toToml
   |> cfg.toLeanConfig.toToml
+where
+  smartInsertVerTags (pat : StrPat) (t : Table) : Table :=
+    match pat with
+    | .mem s => t.insert `versionTags (toToml s)
+    | .startsWith p => t.insert `versionTags.startsWith (toToml p)
+    | .satisfies _ n =>
+      if n.isAnonymous || n == `default then t else
+      t.insert `versionTags.preset (toToml n)
 
 instance : ToToml PackageConfig := ⟨(toToml ·.toToml)⟩
 
diff --git a/src/lake/Lake/Config/Package.lean b/src/lake/Lake/Config/Package.lean
index 5d81785290c3..7e2b67d7cc2a 100644
--- a/src/lake/Lake/Config/Package.lean
+++ b/src/lake/Lake/Config/Package.lean
@@ -14,6 +14,7 @@ import Lake.Config.Script
 import Lake.Load.Config
 import Lake.Util.DRBMap
 import Lake.Util.OrdHashSet
+import Lake.Util.Version
 
 open System Lean
 
@@ -23,6 +24,56 @@ namespace Lake
 @[inline] def defaultBuildArchive (name : Name) : String :=
   s!"{name.toString false}-{System.Platform.target}.tar.gz"
 
+/-- A `String` pattern. Matches some subset of strings. -/
+inductive StrPat
+/--
+Matches a string that satisfies an arbitrary predicate
+(optionally identified by a `Name`).
+-/
+| satisfies (f : String → Bool) (name := Name.anonymous)
+/-- Matches a string that is a member of the the array -/
+| mem (xs : Array String)
+/-- Matches a string that starts with this prefix. -/
+| startsWith (pre : String)
+deriving Inhabited
+
+instance : Coe (Array String) StrPat := ⟨.mem⟩
+instance : Coe (String → Bool) StrPat := ⟨.satisfies⟩
+
+/-- Matches nothing. -/
+def StrPat.none : StrPat := .mem #[]
+
+instance : EmptyCollection StrPat := ⟨.none⟩
+
+/--
+Whether a string is "version-like".
+That is, a `v` followed by a digit.
+-/
+def isVerLike (s : String) : Bool :=
+  if h : s.utf8ByteSize ≥ 2 then
+    s.get' 0 (by simp [String.atEnd]; omega) == 'v' &&
+    (s.get' ⟨1⟩ (by simp [String.atEnd]; omega)).isDigit
+  else
+    false
+
+/-- Matches a "version-like" string: a `v` followed by a digit. -/
+def StrPat.verLike : StrPat := .satisfies isVerLike `verLike
+
+/-- Default string pattern for a Package's `versionTags`. -/
+def defaultVersionTags := StrPat.satisfies isVerLike `default
+
+/-- Builtin `StrPat` presets available to TOML for `versionTags`. -/
+def versionTagPresets :=
+  NameMap.empty
+  |>.insert `verLike .verLike
+  |>.insert `default defaultVersionTags
+
+/-- Returns whether the string `s` matches the pattern. -/
+def StrPat.matches (s : String) : (self : StrPat) → Bool
+| .satisfies f _ => f s
+| .mem xs => xs.contains s
+| .startsWith p => p.isPrefixOf s
+
 --------------------------------------------------------------------------------
 /-! # PackageConfig -/
 --------------------------------------------------------------------------------
@@ -183,6 +234,127 @@ structure PackageConfig extends WorkspaceConfig, LeanConfig where
   -/
   lintDriverArgs : Array String := #[]
 
+  /--
+  The package version. Versions have the form:
+
+  ```
+  v!"<major>.<minor>.<patch>[-<specialDescr>]"
+  ```
+
+  A version with a `-` suffix is considered a "prerelease".
+
+  Lake suggest the following guidelines for incrementing versions:
+
+  * **Major version increment** *(e.g., v1.3.0 → v2.0.0)*
+    Indicates significant breaking changes in the package.
+    Package users are not expected to update to the new version
+    without manual intervention.
+
+  * **Minor version increment** *(e.g., v1.3.0 → v1.4.0)*
+    Denotes notable changes that are expected to be
+    generally backwards compatible.
+    Package users are expected to update to this version automatically
+    and should be able to fix any breakages and/or warnings easily.
+
+  * **Patch version increment** *(e.g., v1.3.0 → v1.3.1)*
+    Reserved for bug fixes and small touchups.
+    Package users are expected to update automatically and should not expect
+    significant breakage, except in the edge case of users relying on the
+    behavior of patched bugs.
+
+  **Note that backwards-incompatible changes may occur at any version increment.**
+  The is because the current nature of Lean (e.g., transitive imports,
+  rich metaprogramming, reducibility in proofs), makes it infeasible to
+  define a completely stable interface for a package.
+  Instead, the different version levels indicate a change's intended significance
+  and how difficult migration is expected to be.
+
+  Versions of form the `0.x.x` are considered development versions prior to
+  first official release. Like prerelease, they are not expected to closely
+  follow the above guidelines.
+
+  Packages without a defined version default to `0.0.0`.
+  -/
+  version : StdVer := v!"0.0.0"
+
+  /--
+  Git tags of this package's repository that should be treated as versions.
+  Package indices (e.g., Reservoir) can make use of this information to determine
+  the Git revisions corresponding to released versions.
+
+  Defaults to tags that are "version-like".
+  That is, start with a `v` and are followed by a digit.
+  -/
+  versionTags : StrPat := defaultVersionTags
+
+  /-- A short description for the package (e.g., for Reservoir). -/
+  description : String := ""
+
+  /--
+  Custom keywords associated with the package.
+  Reservoir can make use of a package's keywords to group related packages
+  together and make it easier for users to discover them.
+
+  Good keywords include the domain (e.g., `math`, `software-verification`,
+  `devtool`), specific subtopics (e.g., `topology`,  `cryptology`), and
+  significant implementation details (e.g., `dsl`, `ffi`, `cli`).
+  For instance, Lake's keywords could be `devtool`, `cli`, `dsl`,
+  `package-manager`, `build-system`.
+  -/
+  keywords : Array String := #[]
+
+  /--
+  A URL to information about the package.
+
+  Reservoir will already include a link to the package's GitHub repository
+  (if the package is sourced from there). Thus, users are advised to specify
+  something else for this link (if anything).
+  -/
+  homepage : String := ""
+
+  /--
+  The package's license (if one).
+  Should be a valid [SPDX License Expression][1].
+
+  Reservoir requires that packages uses an OSI-approved license to be
+  included in its index, and currently only supports single identifier
+  SPDX expressions. For, a list of OSI-approved SPDX license identifiers,
+  see the [SPDX LIcense List][2].
+
+  [1]: https://spdx.github.io/spdx-spec/v3.0/annexes/SPDX-license-expressions/
+  [2]: https://spdx.org/licenses/
+  -/
+  license : String := ""
+
+  /--
+  Files containing licensing information for the package.
+
+  These should be the license files that users are expected to include when
+  distributing package sources, which may be more then one file for some licenses.
+  For example, the Apache 2.0 license requires the reproduction of a `NOTICE`
+  file along with the license (if such a file exists).
+
+  Defaults to `#["LICENSE"]`.
+  -/
+  licenseFiles : Array FilePath := #["LICENSE"]
+
+  /--
+  The path to the package's README.
+  A README should be a markdown file containing an overview of the package.
+  Reservoir displays the rendered HTML of this README on a package's page.
+
+  Defaults to `README.md`.
+  -/
+  readmeFile : FilePath := "README.md"
+
+  /--
+  Whether Reservoir should include the package in its index.
+  When set to `false`, Reservoir will not add the package to its index
+  and will remove it if it was already there (when Reservoir is next updated).
+  -/
+  reservoir : Bool := true
+
+
 deriving Inhabited
 
 --------------------------------------------------------------------------------
@@ -287,6 +459,50 @@ structure PostUpdateHookDecl where
 
 namespace Package
 
+/-- The package version. -/
+@[inline] def version (self : Package) : LeanVer  :=
+  self.config.version
+
+/-- The package's `versionTags` configuration. -/
+@[inline] def versionTags (self : Package) : StrPat  :=
+  self.config.versionTags
+
+/-- The package's `description` configuration. -/
+@[inline] def description (self : Package) : String  :=
+  self.config.description
+
+/-- The package's `keywords` configuration. -/
+@[inline] def keywords (self : Package) : Array String  :=
+  self.config.keywords
+
+/-- The package's `homepage` configuration. -/
+@[inline] def homepage (self : Package) : String  :=
+  self.config.homepage
+
+/-- The package's `reservoir` configuration. -/
+@[inline] def reservoir (self : Package) : Bool  :=
+  self.config.reservoir
+
+/-- The package's `license` configuration. -/
+@[inline] def license (self : Package) : String  :=
+  self.config.license
+
+/-- The package's `licenseFiles` configuration. -/
+@[inline] def relLicenseFiles (self : Package) : Array FilePath  :=
+  self.config.licenseFiles
+
+/-- The package's `dir` joined with each of its `relLicenseFiles`. -/
+@[inline] def licenseFiles (self : Package) : Array FilePath  :=
+  self.relLicenseFiles.map (self.dir / ·)
+
+/-- The package's `readmeFile` configuration. -/
+@[inline] def relReadmeFile (self : Package) : FilePath  :=
+  self.config.readmeFile
+
+/-- The package's `dir` joined with its `relReadmeFile`. -/
+@[inline] def readmeFile (self : Package) : FilePath  :=
+  self.dir / self.config.readmeFile
+
 /-- The package's direct dependencies. -/
 @[inline] def deps (self : Package) : Array Package  :=
   self.opaqueDeps.map (·.get)
diff --git a/src/lake/Lake/Load/Manifest.lean b/src/lake/Lake/Load/Manifest.lean
index 6fee2fa8b680..9fad82437a60 100644
--- a/src/lake/Lake/Load/Manifest.lean
+++ b/src/lake/Lake/Load/Manifest.lean
@@ -49,7 +49,7 @@ That is, Lake ignores the `-` suffix.
 - `"1.0.0"`: Switches to a semantic versioning scheme
 - `"1.1.0"`: Add optional `scope` package entry field
 -/
-@[inline] def Manifest.version : LeanVer := v!"1.1.0"
+@[inline] def Manifest.version : StdVer := v!"1.1.0"
 
 /-- Manifest version `0.6.0` package entry. For backwards compatibility. -/
 inductive PackageEntryV6
@@ -195,7 +195,7 @@ protected def fromJson? (json : Json) : Except String Manifest := do
   let ver : SemVerCore ←
     match (← obj.get "version" : Json) with
     | (n : Nat) => pure {minor := n}
-    | (s : String) => LeanVer.parse s
+    | (s : String) => StdVer.parse s
     | ver => throw s!"unknown manifest version format '{ver}'; \
       you may need to update your 'lean-toolchain'"
   if ver.major > 1 then
diff --git a/src/lake/Lake/Load/Toml.lean b/src/lake/Lake/Load/Toml.lean
index 02ad78e05d3e..519231a7c989 100644
--- a/src/lake/Lake/Load/Toml.lean
+++ b/src/lake/Lake/Load/Toml.lean
@@ -136,6 +136,30 @@ def decodeLeanOptions (v : Value) : Except (Array DecodeError) (Array LeanOption
   | v =>
     throw #[.mk v.ref "expected array or table"]
 
+protected def StdVer.decodeToml (v : Value) : Except (Array DecodeError) LeanVer := do
+  match StdVer.parse (← v.decodeString) with
+  | .ok v => return v
+  | .error e => throw #[.mk v.ref e]
+
+instance : DecodeToml StdVer := ⟨(StdVer.decodeToml ·)⟩
+
+protected def StrPat.decodeToml (v : Value) (presets : NameMap StrPat := {}) : Except (Array DecodeError) StrPat :=
+  match v with
+  | .array _ vs => .mem <$> decodeArray vs
+  | .table r t => do
+    if let some pre ← t.decode? `startsWith then
+      return .startsWith pre
+    else if let some name ← t.decode? `preset then
+      if let some preset := presets.find? name then
+        return preset
+      else
+        throw #[.mk r s!"unknown preset '{name}'"]
+    else
+      throw #[.mk r "expected 'startsWith' or 'preset'"]
+  | v => throw #[.mk v.ref "expected array or table"]
+
+instance : DecodeToml StrPat := ⟨(StrPat.decodeToml ·)⟩
+
 /-! ## Configuration Decoders -/
 
 protected def WorkspaceConfig.decodeToml (t : Table) : Except (Array DecodeError) WorkspaceConfig := ensureDecode do
@@ -182,13 +206,25 @@ protected def PackageConfig.decodeToml (t : Table) (ref := Syntax.missing) : Exc
   let testDriverArgs ← t.tryDecodeD `testDriverArgs #[]
   let lintDriver ← t.tryDecodeD `lintDriver ""
   let lintDriverArgs ← t.tryDecodeD `lintDriverArgs #[]
+  let version : StdVer ← t.tryDecodeD `version v!"0.0.0"
+  let versionTags ← optDecodeD defaultVersionTags (t.find? `versionTags)
+    <| StrPat.decodeToml (presets := versionTagPresets)
+  let description ← t.tryDecodeD `description ""
+  let keywords ← t.tryDecodeD `keywords #[]
+  let homepage ← t.tryDecodeD `homepage ""
+  let license ← t.tryDecodeD `license ""
+  let licenseFiles : Array FilePath ← t.tryDecodeD `licenseFiles #["LICENSE"]
+  let readmeFile ← t.tryDecodeD `readmeFile "README.md"
+  let reservoir ← t.tryDecodeD `reservoir true
   let toLeanConfig ← tryDecode <| LeanConfig.decodeToml t
   let toWorkspaceConfig ← tryDecode <| WorkspaceConfig.decodeToml t
   return {
-    name, precompileModules, moreGlobalServerArgs,
-    srcDir, buildDir, leanLibDir, nativeLibDir, binDir, irDir,
+    name, precompileModules, moreGlobalServerArgs
+    srcDir, buildDir, leanLibDir, nativeLibDir, binDir, irDir
     releaseRepo, buildArchive?, preferReleaseBuild
     testDriver, testDriverArgs, lintDriver, lintDriverArgs
+    version, versionTags, description, keywords, homepage, reservoir
+    license, licenseFiles, readmeFile
     toLeanConfig, toWorkspaceConfig
   }
 
diff --git a/src/lake/Lake/Toml/Data/Value.lean b/src/lake/Lake/Toml/Data/Value.lean
index fb0618837d69..be64ef8d875d 100644
--- a/src/lake/Lake/Toml/Data/Value.lean
+++ b/src/lake/Lake/Toml/Data/Value.lean
@@ -107,7 +107,9 @@ def ppTable (t : Table) : String :=
   let (ts, fs) := t.items.foldl (init := ("", "")) fun (ts, fs) (k,v) =>
     match v with
     | .array _ vs =>
-      if vs.all (· matches .table ..) then
+      if vs.isEmpty then
+        (ts.append s!"{ppKey k} = []\n", fs)
+      else if vs.all (· matches .table ..) then
         let fs := vs.foldl (init := fs) fun s v =>
           match v with
           | .table _ t =>
diff --git a/src/lake/Lake/Toml/Decode.lean b/src/lake/Lake/Toml/Decode.lean
index 9a3837482541..5c2b3559448f 100644
--- a/src/lake/Lake/Toml/Decode.lean
+++ b/src/lake/Lake/Toml/Decode.lean
@@ -158,6 +158,10 @@ instance : DecodeToml Table := ⟨(·.decodeTable)⟩
 
 end Value
 
+def decodeKeyval [dec : DecodeToml α] (k : Name) (v : Value) : Except (Array DecodeError) α := do
+  dec.decode v |>.mapError fun xs => xs.map fun x =>
+    {x with msg := s!"key {ppKey k}: " ++ x.msg}
+
 namespace Table
 
 @[inline] def decodeValue (t : Table) (k : Name) (ref := Syntax.missing) : Except DecodeError Value := do
@@ -167,8 +171,10 @@ namespace Table
 
 def decode [dec : DecodeToml α] (t : Table) (k : Name) (ref := Syntax.missing) : Except (Array DecodeError) α := do
   let a ← t.decodeValue k ref
-  dec.decode a |>.mapError fun xs => xs.map fun x =>
-    {x with msg := s!"key {ppKey k}: " ++ x.msg}
+  decodeKeyval (dec := dec) k a
+
+def decode? [dec : DecodeToml α] (t : Table) (k : Name) : Except (Array DecodeError) (Option α) := do
+  t.find? k |>.mapM fun v => decodeKeyval (dec := dec) k v
 
 def decodeNameMap [dec : DecodeToml α] (t : Toml.Table) : Except (Array DecodeError) (NameMap α) := do
   t.items.foldl (init := Except.ok {}) fun m (k,v) =>
diff --git a/src/lake/Lake/Util/Git.lean b/src/lake/Lake/Util/Git.lean
index ef8333b0f00f..4aba5477b888 100644
--- a/src/lake/Lake/Util/Git.lean
+++ b/src/lake/Lake/Util/Git.lean
@@ -38,6 +38,7 @@ end Git
 structure GitRepo where
   dir : FilePath
 
+instance : Coe FilePath GitRepo := ⟨(⟨·⟩)⟩
 instance : ToString GitRepo := ⟨(·.dir.toString)⟩
 
 namespace GitRepo
@@ -101,6 +102,10 @@ def findRemoteRevision (repo : GitRepo) (rev? : Option String := none) (remote :
 @[inline] def revisionExists (rev : String) (repo : GitRepo) : BaseIO Bool := do
   repo.testGit #["rev-parse", "--verify", rev ++ "^{commit}"]
 
+@[inline] def getTags (repo : GitRepo) : BaseIO (List String) := do
+  let some out ← repo.captureGit? #["tag"] | return []
+  return out.split (· == '\n')
+
 @[inline] def findTag? (rev : String := "HEAD") (repo : GitRepo) : BaseIO (Option String) := do
   repo.captureGit? #["describe", "--tags", "--exact-match", rev]
 
diff --git a/src/lake/Lake/Util/Version.lean b/src/lake/Lake/Util/Version.lean
index 4a81f6102dd4..1a96a5d3644c 100644
--- a/src/lake/Lake/Util/Version.lean
+++ b/src/lake/Lake/Util/Version.lean
@@ -60,18 +60,21 @@ instance : ToExpr SemVerCore where
 A Lean-style semantic version.
 A major-minor-patch triple with an optional arbitrary `-` suffix.
 -/
-structure LeanVer extends SemVerCore where
+structure StdVer extends SemVerCore where
   specialDescr : String := ""
   deriving Inhabited, Repr, DecidableEq
 
-instance : Coe LeanVer SemVerCore := ⟨LeanVer.toSemVerCore⟩
+/-- A Lean version. -/
+abbrev LeanVer := StdVer
 
-@[inline] protected def LeanVer.ofSemVerCore (ver : SemVerCore) : LeanVer :=
+instance : Coe StdVer SemVerCore := ⟨StdVer.toSemVerCore⟩
+
+@[inline] protected def StdVer.ofSemVerCore (ver : SemVerCore) : StdVer :=
   {toSemVerCore := ver, specialDescr := ""}
 
-instance : Coe SemVerCore LeanVer := ⟨LeanVer.ofSemVerCore⟩
+instance : Coe SemVerCore StdVer := ⟨StdVer.ofSemVerCore⟩
 
-protected def LeanVer.compare (a b : LeanVer) : Ordering :=
+protected def StdVer.compare (a b : StdVer) : Ordering :=
   match compare a.toSemVerCore b.toSemVerCore with
   | .eq =>
     match a.specialDescr, b.specialDescr with
@@ -81,14 +84,14 @@ protected def LeanVer.compare (a b : LeanVer) : Ordering :=
     | a, b => compare a b
   | ord => ord
 
-instance : Ord LeanVer := ⟨LeanVer.compare⟩
+instance : Ord StdVer := ⟨StdVer.compare⟩
 
-instance : LT LeanVer := ltOfOrd
-instance : LE LeanVer := leOfOrd
-instance : Min LeanVer := minOfLe
-instance : Max LeanVer := maxOfLe
+instance : LT StdVer := ltOfOrd
+instance : LE StdVer := leOfOrd
+instance : Min StdVer := minOfLe
+instance : Max StdVer := maxOfLe
 
-def LeanVer.parse (ver : String) : Except String LeanVer := do
+def StdVer.parse (ver : String) : Except String StdVer := do
   let sepPos := ver.find (· == '-')
   if h : ver.atEnd sepPos then
     SemVerCore.parse ver
@@ -99,20 +102,20 @@ def LeanVer.parse (ver : String) : Except String LeanVer := do
       throw "invalid Lean version: '-' suffix cannot be empty"
     return {toSemVerCore := core, specialDescr}
 
-protected def LeanVer.toString (ver : LeanVer) : String :=
+protected def StdVer.toString (ver : StdVer) : String :=
   if ver.specialDescr.isEmpty then
     ver.toSemVerCore.toString
   else
     s!"{ver.toSemVerCore}-{ver.specialDescr}"
 
-instance : ToString LeanVer := ⟨LeanVer.toString⟩
-instance : ToJson LeanVer := ⟨(·.toString)⟩
-instance : FromJson LeanVer := ⟨(do LeanVer.parse <| ← fromJson? ·)⟩
+instance : ToString StdVer := ⟨StdVer.toString⟩
+instance : ToJson StdVer := ⟨(·.toString)⟩
+instance : FromJson StdVer := ⟨(do StdVer.parse <| ← fromJson? ·)⟩
 
-instance : ToExpr LeanVer where
-  toExpr ver := mkAppN (mkConst ``LeanVer.mk)
+instance : ToExpr StdVer where
+  toExpr ver := mkAppN (mkConst ``StdVer.mk)
     #[toExpr ver.toSemVerCore, toExpr ver.specialDescr]
-  toTypeExpr := mkConst ``LeanVer
+  toTypeExpr := mkConst ``StdVer
 
 /-! ## Version Literals
 
@@ -130,7 +133,7 @@ class DecodeVersion (α : Type u) where
 export DecodeVersion (decodeVersion)
 
 instance : DecodeVersion SemVerCore := ⟨SemVerCore.parse⟩
-instance : DecodeVersion LeanVer := ⟨LeanVer.parse⟩
+@[default_instance] instance : DecodeVersion StdVer := ⟨StdVer.parse⟩
 
 private def toResultExpr [ToExpr α] (x : Except String α) : Except String Expr :=
   Functor.map toExpr x
diff --git a/src/lake/tests/driver/build.lean b/src/lake/tests/driver/build.lean
new file mode 100644
index 000000000000..b139f75ece72
--- /dev/null
+++ b/src/lake/tests/driver/build.lean
@@ -0,0 +1,7 @@
+import Lake
+open System Lake DSL
+
+package test
+
+@[default_target]
+target foo : Unit := pure .nil
diff --git a/src/lake/tests/driver/build.toml b/src/lake/tests/driver/build.toml
new file mode 100644
index 000000000000..a16b885e4dd3
--- /dev/null
+++ b/src/lake/tests/driver/build.toml
@@ -0,0 +1,2 @@
+name = "test"
+defaultTargets = ["bogus"]
diff --git a/src/lake/tests/driver/test.sh b/src/lake/tests/driver/test.sh
index 29f1538f1072..38ef61d505ec 100755
--- a/src/lake/tests/driver/test.sh
+++ b/src/lake/tests/driver/test.sh
@@ -84,3 +84,9 @@ $LAKE -f none.lean check-test && exit 1 || true
 $LAKE -f none.toml check-test && exit 1 || true
 $LAKE -f none.lean check-lint && exit 1 || true
 $LAKE -f none.toml check-lint && exit 1 || true
+
+# Build checker
+$LAKE -f build.lean check-build
+$LAKE -f build.toml check-build
+$LAKE -f none.lean check-build && exit 1 || true
+$LAKE -f none.toml check-build && exit 1 || true
diff --git a/src/lake/tests/reservoirConfig/clean.sh b/src/lake/tests/reservoirConfig/clean.sh
new file mode 100755
index 000000000000..8e49561ad81b
--- /dev/null
+++ b/src/lake/tests/reservoirConfig/clean.sh
@@ -0,0 +1 @@
+rm -rf .lake lake-manifest.json .git
diff --git a/src/lake/tests/reservoirConfig/expected.json b/src/lake/tests/reservoirConfig/expected.json
new file mode 100644
index 000000000000..5f5a734ed823
--- /dev/null
+++ b/src/lake/tests/reservoirConfig/expected.json
@@ -0,0 +1,12 @@
+{"versionTags": ["v1", "v2"],
+ "version": "0.0.0",
+ "schemaVersion": "1.0.0",
+ "readmeFile": null,
+ "platformIndependent": null,
+ "name": "test",
+ "licenseFiles": [],
+ "license": "",
+ "keywords": ["test-case"],
+ "homepage": "https://example.com",
+ "doIndex": true,
+ "description": "Tests Reservoir configuration"}
diff --git a/src/lake/tests/reservoirConfig/lakefile.lean b/src/lake/tests/reservoirConfig/lakefile.lean
new file mode 100644
index 000000000000..47fd098fc94f
--- /dev/null
+++ b/src/lake/tests/reservoirConfig/lakefile.lean
@@ -0,0 +1,7 @@
+import Lake
+open Lake DSL
+
+package test where
+  keywords := #["test-case"]
+  homepage := "https://example.com"
+  description := "Tests Reservoir configuration"
diff --git a/src/lake/tests/reservoirConfig/test.sh b/src/lake/tests/reservoirConfig/test.sh
new file mode 100755
index 000000000000..bf47fa04c45d
--- /dev/null
+++ b/src/lake/tests/reservoirConfig/test.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+LAKE=${LAKE:-../../.lake/build/bin/lake}
+
+./clean.sh
+
+git init
+git checkout -b master
+git config user.name test
+git config user.email test@example.com
+git add --all
+git commit -m "commit 1"
+git tag v1
+git commit --allow-empty -m "commit 2"
+git tag v2
+git commit --allow-empty -m "commit 3"
+git tag etc
+
+$LAKE reservoir-config | diff -u --strip-trailing-cr expected.json -
+
+# Cleanup git repo
+rm -rf .git
diff --git a/src/lake/tests/translateConfig/source.lean b/src/lake/tests/translateConfig/source.lean
index 0ba45edf6e7f..a156ace83626 100644
--- a/src/lake/tests/translateConfig/source.lean
+++ b/src/lake/tests/translateConfig/source.lean
@@ -31,6 +31,15 @@ package test where
   packagesDir := defaultPackagesDir
   leanOptions := #[⟨`pp.unicode.fun, true⟩]
   lintDriver := "b"
+  version := v!"0.0.0"
+  versionTags := fun _ : String => false
+  description := ""
+  keywords := #[]
+  homepage := ""
+  license := ""
+  licenseFiles := #["LICENSE"]
+  readmeFile := "README.md"
+  reservoir := true
 
 require "foo" / "baz" @ "git#abcdef"
 require foo from "dir" with NameMap.empty.insert `foo "bar"
diff --git a/src/lake/tests/translateConfig/source.toml b/src/lake/tests/translateConfig/source.toml
index 885c786c6930..6eadac1cfc9d 100644
--- a/src/lake/tests/translateConfig/source.toml
+++ b/src/lake/tests/translateConfig/source.toml
@@ -27,6 +27,15 @@ moreLinkArgs = []
 weakLinkArgs = []
 backend = "default"
 platformIndependent = true
+version = "0.0.0"
+versionTags = {preset = "default"}
+description = ""
+keywords = []
+homepage = ""
+license = ""
+licenseFiles = ["LICENSE"]
+readmeFile = "README.md"
+reservoir = true
 
 [[lean_lib]]
 name = "A"
diff --git a/src/lake/tests/versionTags/clean.sh b/src/lake/tests/versionTags/clean.sh
new file mode 100755
index 000000000000..8e49561ad81b
--- /dev/null
+++ b/src/lake/tests/versionTags/clean.sh
@@ -0,0 +1 @@
+rm -rf .lake lake-manifest.json .git
diff --git a/src/lake/tests/versionTags/lakefile.lean b/src/lake/tests/versionTags/lakefile.lean
new file mode 100644
index 000000000000..eadfb1bf2b12
--- /dev/null
+++ b/src/lake/tests/versionTags/lakefile.lean
@@ -0,0 +1,4 @@
+import Lake
+open Lake DSL
+
+package test
diff --git a/src/lake/tests/versionTags/test.sh b/src/lake/tests/versionTags/test.sh
new file mode 100755
index 000000000000..b223f5dcd522
--- /dev/null
+++ b/src/lake/tests/versionTags/test.sh
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+LAKE=${LAKE:-../../.lake/build/bin/lake}
+
+./clean.sh
+
+git init
+git checkout -b master
+git config user.name test
+git config user.email test@example.com
+git add --all
+git commit -m "commit 1"
+git tag v1
+git commit --allow-empty -m "commit 2"
+git tag v2
+git commit --allow-empty -m "commit 3"
+git tag etc
+
+$LAKE version-tags | diff -u --strip-trailing-cr <(cat << 'EOF'
+v1
+v2
+EOF
+) -
+
+# Cleanup git repo
+rm -rf .git