Add quiet mode feature for agentic workflows (#10)

* Add workflow documentation in CLAUDE.md

Documents project structure, build commands, testing workflow, and development setup for future reference.

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Co-Authored-By: Claude <[email protected]>

* Add SKIP_S3_TESTS option to test runner

- Tests marked with `# s3` directive now skippable via SKIP_S3_TESTS=1
- Allows running 35/50 tests without S3 credentials
- Updated CLAUDE.md with usage instructions and S3 requirements

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Co-Authored-By: Claude <[email protected]>

* Add local settings for Claude permissions

This commit introduces a new configuration file, settings.local.json, which defines the permissions for various Bash commands used in the Claude environment. The allowed commands include stack build, git add, git commit, stack test, find, and stack build with specific arguments. No commands are currently denied or require confirmation.

* Auto-detect S3 credentials and skip tests with clear reporting

- Tests automatically skip when S3 environment variables are missing
- Clear informative messages explain test execution (e.g. "Running 35/50 tests")
- Provides guidance on enabling S3 tests when credentials are absent
- Maintains backward compatibility with SKIP_S3_TESTS=1 override
- Enables agentic workflows to use `stack test` without environment exports

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Co-Authored-By: Claude <[email protected]>

* Add quiet mode feature for agentic workflows

- Task output suppressed from terminal unless task fails
- Successful tasks: output goes only to log files (clean terminal)
- Failed tasks: full buffered output displayed for debugging
- Enabled via TASKRUNNER_QUIET=1 environment variable
- Added # quiet test directive and comprehensive test coverage
- All existing functionality preserved, no regressions

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Co-Authored-By: Claude <[email protected]>

* Add comprehensive nested task tests for quiet mode

- quiet-mode-nested-success: No output when all nested tasks succeed
- quiet-mode-nested-parent-fail: Shows parent output when parent fails
- quiet-mode-nested-child-fail: Shows child output when child fails
- Validates that quiet mode works correctly in complex nested scenarios
- Each task process maintains its own buffer, only failing process shows output

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Co-Authored-By: Claude <[email protected]>

* Update Claude settings and add research documentation

* Refactor testing documentation and clarify quiet mode feature

- Updated CLAUDE.md to remove explicit S3 test skipping section.
- Revised testing commands in README.md for consistency and clarity.
- Expanded test structure and directives information.
- Introduced a comprehensive section on the new quiet mode feature in task output handling.
- Enhanced explanations for output behavior in quiet mode and its integration with nested tasks and exit codes in task-output-handling.md.

* Update research documentation with proper metadata header

- Added YAML front matter with date, researcher, git commit, branch info
- Included comprehensive tags for searchability
- Enhanced task-output-handling.md with complete quiet mode documentation
- Updated Claude settings to allow additional git commands

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: zyla

.claude/settings.local.json

@@ -0,0 +1,18 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(stack build)",
+      "Bash(git add:*)",
+      "Bash(git commit:*)",
+      "Bash(stack test)",
+      "Bash(stack test:*)",
+      "Bash(find:*)",
+      "Bash(stack build:*)",
+      "Bash(mkdir:*)",
+      "Bash(git rev-parse:*)",
+      "Bash(git remote get-url:*)"
+    ],
+    "deny": [],
+    "ask": []
+  }
+}

CLAUDE.md

@@ -0,0 +1,83 @@
+# Claude Code Workflow Instructions for taskrunner
+
+## Project Overview
+This is a Haskell project that implements a task runner with caching, parallel execution, and remote storage capabilities. It uses Stack for build management and tasty-golden for snapshot testing.
+
+## Project Structure
+- `src/` - Haskell source code (main library)
+- `app/` - Executable main entry point
+- `test/` - Test suite
+  - `test/t/` - Golden test files (`.txt` input, `.out` expected output)
+  - `test/Spec.hs` - Main test runner
+  - `test/FakeGithubApi.hs` - Mock GitHub API for testing
+- `package.yaml` - Haskell package configuration (Stack format)
+- `stack.yaml` - Stack resolver and build configuration
+- `taskrunner.cabal` - Generated cabal file (don't edit directly)
+
+## Build and Development Workflow
+
+### Building the Project
+```bash
+stack build
+```
+
+### Running Tests
+```bash
+# Run tests (auto-detects S3 credentials and skips S3 tests if missing)
+stack test
+
+# Run tests, skipping slow ones
+export SKIP_SLOW_TESTS=1
+stack test
+
+# Run specific test by pattern
+stack test --test-arguments "--pattern hello"
+
+# List all available tests
+stack test --test-arguments "--list-tests"
+```
+
+### Accepting Golden Test Changes
+When golden tests fail due to expected output changes:
+```bash
+stack test --test-arguments --accept
+```
+
+### Test Structure
+- Test files are in `test/t/` directory
+- Each test has:
+  - `.txt` file - shell script to execute
+  - `.out` file - expected output (golden file)
+- Tests run through the taskrunner executable
+- Special comments in `.txt` files control test behavior:
+  - `# check output` - check stdout/stderr
+  - `# check github` - check GitHub API calls
+  - `# no toplevel` - don't wrap in taskrunner
+  - `# s3` - enable S3 testing
+  - `# github keys` - provide GitHub credentials
+
+## Key Commands for Development
+
+### Building
+- `stack build` - Build the project
+- `stack build --fast` - Fast build (less optimization)
+- `stack clean` - Clean build artifacts
+
+### Testing
+- `stack test` - Run all tests
+- `stack test --test-arguments --accept` - Accept golden test changes
+- `SKIP_SLOW_TESTS=1 stack test` - Skip slow tests
+
+### Running the executable
+- `stack exec taskrunner -- [args]` - Run the built executable
+- `stack run -- [args]` - Build and run in one command
+
+## Notes
+- This project uses tasty-golden for snapshot/golden file testing
+- The test suite includes integration tests that verify taskrunner behavior
+- **S3 Test Auto-Detection**: 15 tests require S3 credentials (marked with `# s3` directive in test files)
+  - `stack test` automatically skips S3 tests if credentials are missing
+  - To run S3 tests, set: `TASKRUNNER_TEST_S3_ENDPOINT`, `TASKRUNNER_TEST_S3_ACCESS_KEY`, `TASKRUNNER_TEST_S3_SECRET_KEY`
+- GitHub tests use a fake API server and don't require real GitHub credentials
+- The project uses Universum as an alternative Prelude
+- Build output and temporary files are in `.stack-work/`

README.md

@@ -144,13 +144,61 @@ The `snapshot` command supports the following flags:
 - `--long-running`: Indicates that the task is expected to run for a long time (e.g. a server). Currently doens't have any effect though, TODO: can we remove it?
 
 
-## Tests: Update Golden Files
+## Testing
 
 This project uses [tasty-golden](https://github.com/UnkindPartition/tasty-golden) for snapshot-based testing.
 
-To update the golden files, run the test suite with the `--accept` flag passed to the test executable.
-If you're using stack, the full command is:
+### Running Tests
 
-```sh
+```bash
+# Run all tests (auto-detects S3 credentials)
+stack test
+
+# Run tests, skipping slow ones for faster development
+export SKIP_SLOW_TESTS=1
+stack test
+
+# Run specific test by pattern
+stack test --test-arguments "--pattern hello"
+
+# List all available tests
+stack test --test-arguments "--list-tests"
+```
+
+### Test Structure
+
+Tests are located in `test/t/` directory with two files per test:
+- `.txt` file - Shell script to execute
+- `.out` file - Expected output (golden file)
+
+#### Test Directives
+
+Special comments in `.txt` files control test behavior:
+- `# check output` - Check stdout/stderr (default)
+- `# check github` - Check GitHub API calls
+- `# no toplevel` - Don't wrap in taskrunner
+- `# s3` - Requires S3 credentials (auto-skipped if missing)
+- `# github keys` - Provide GitHub credentials
+- `# quiet` - Run in quiet mode
+
+### S3 Test Auto-Detection
+
+15 tests require S3 credentials and are automatically skipped if credentials are missing.
+
+To run S3 tests, set these environment variables:
+```bash
+export TASKRUNNER_TEST_S3_ENDPOINT=your-s3-endpoint
+export TASKRUNNER_TEST_S3_ACCESS_KEY=your-access-key
+export TASKRUNNER_TEST_S3_SECRET_KEY=your-secret-key
+stack test
+```
+
+### Accepting Golden Test Changes
+
+When golden tests fail due to expected output changes:
+
+```bash
 stack test --test-arguments --accept
 ```
+
+This updates the `.out` files with new expected output. Review changes carefully before committing.

src/App.hs

@@ -62,6 +62,7 @@ getSettings = do
   fuzzyCacheFallbackBranches <- maybe [] (Text.words . toText) <$> lookupEnv "TASKRUNNER_FALLBACK_BRANCHES"
   primeCacheMode <- (==Just "1") <$> lookupEnv "TASKRUNNER_PRIME_CACHE_MODE"
   mainBranch <- map toText <$> lookupEnv "TASKRUNNER_MAIN_BRANCH"
+  quietMode <- (==Just "1") <$> lookupEnv "TASKRUNNER_QUIET"
   pure Settings
         { stateDirectory
         , rootDirectory
@@ -76,6 +77,7 @@ getSettings = do
         , primeCacheMode
         , mainBranch
         , force = False
+        , quietMode
         }
 
 main :: IO ()
@@ -129,7 +131,7 @@ main = do
     -- Recursive: AppState is used before process is started (mostly for logging)
     rec
 
-      appState <- AppState settings jobName buildId isToplevel <$> newIORef Nothing <*> newIORef Nothing <*> newIORef False <*> pure toplevelStderr <*> pure subprocessStderr <*> pure logFile
+      appState <- AppState settings jobName buildId isToplevel <$> newIORef Nothing <*> newIORef Nothing <*> newIORef False <*> pure toplevelStderr <*> pure subprocessStderr <*> pure logFile <*> newIORef []
         <*> newIORef Nothing
 
       when (isToplevel && appState.settings.enableCommitStatus) do
@@ -171,6 +173,12 @@ main = do
 
     skipped <- readIORef appState.skipped
 
+    -- Handle quiet mode buffer based on exit code
+    when appState.settings.quietMode do
+      if exitCode == ExitSuccess
+        then discardQuietBuffer appState  -- Success: discard buffered output
+        else flushQuietBuffer appState toplevelStderr  -- Failure: show buffered output
+
     logDebug appState $ "Command " <> show (args.cmd : args.args) <> " exited with code " <> show exitCode
     logDebugParent m_parentRequestPipe $ "Subtask " <> toText jobName <> " finished with " <> show exitCode
 

src/Types.hs

@@ -19,6 +19,7 @@ data Settings = Settings
   , primeCacheMode :: Bool
   , mainBranch :: Maybe Text
   , force :: Bool
+  , quietMode :: Bool
   } deriving (Show)
 
 type JobName = String
@@ -49,7 +50,8 @@ data AppState = AppState
   , toplevelStderr :: Handle
   , subprocessStderr :: Handle
   , logOutput :: Handle
-  
+  , quietBuffer :: IORef [ByteString]
+
   -- | Lazily initialized Github client
   , githubClient :: IORef (Maybe GithubClient)
   }

src/Utils.hs

@@ -35,7 +35,14 @@ outputLine appState toplevelOutput streamName line = do
           | otherwise = True
 
     when shouldOutputToToplevel do
-      B8.hPutStrLn toplevelOutput $ timestampStr <> "[" <> jobName <> "] " <> streamName <> " | " <> line
+      let formattedLine = timestampStr <> "[" <> jobName <> "] " <> streamName <> " | " <> line
+      if appState.settings.quietMode
+        then do
+          -- In quiet mode, add to buffer instead of outputting immediately
+          modifyIORef appState.quietBuffer (formattedLine :)
+        else
+          -- Normal mode: output immediately
+          B8.hPutStrLn toplevelOutput formattedLine
 
 logLevel :: MonadIO m => ByteString -> AppState -> Text -> m ()
 logLevel level appState msg =
@@ -121,3 +128,16 @@ getCurrentCommit _appState =
 
 logFileName :: Settings -> BuildId -> JobName -> FilePath
 logFileName settings buildId jobName = settings.stateDirectory </> "builds" </> toString buildId </> "logs" </> (jobName <> ".log")
+
+-- | Flush buffered output to terminal (used when task fails in quiet mode)
+flushQuietBuffer :: AppState -> Handle -> IO ()
+flushQuietBuffer appState toplevelOutput = do
+  buffer <- readIORef appState.quietBuffer
+  -- Output in correct order (buffer was built in reverse)
+  mapM_ (B8.hPutStrLn toplevelOutput) (reverse buffer)
+  -- Clear the buffer after flushing
+  writeIORef appState.quietBuffer []
+
+-- | Discard buffered output (used when task succeeds in quiet mode)
+discardQuietBuffer :: AppState -> IO ()
+discardQuietBuffer appState = writeIORef appState.quietBuffer []

test/Spec.hs

@@ -37,10 +37,34 @@ fakeGithubPort = 12345
 goldenTests :: IO TestTree
 goldenTests = do
   skipSlow <- (==Just "1") <$> lookupEnv "SKIP_SLOW_TESTS"
+  skipS3Explicit <- (==Just "1") <$> lookupEnv "SKIP_S3_TESTS"
+  hasS3Creds <- hasS3Credentials
+  let skipS3 = skipS3Explicit || not hasS3Creds
+
   inputFiles0 <- sort <$> findByExtension [".txt"] "test/t"
+  inputFiles1 <- if skipS3
+    then filterM (fmap not . hasS3Directive) inputFiles0
+    else pure inputFiles0
   let inputFiles
-        | skipSlow = filter (\filename -> not ("/slow/" `isInfixOf` filename)) inputFiles0
-        | otherwise = inputFiles0
+        | skipSlow = filter (\filename -> not ("/slow/" `isInfixOf` filename)) inputFiles1
+        | otherwise = inputFiles1
+
+  -- Print informative message about what tests are running
+  let totalTests = length inputFiles0
+      s3Tests = length inputFiles0 - length inputFiles1
+      slowTests = length inputFiles1 - length inputFiles
+      runningTests = length inputFiles
+
+  when (skipS3 && s3Tests > 0) $ do
+    if skipS3Explicit
+      then System.IO.putStrLn $ "SKIP_S3_TESTS=1 - skipping " <> show s3Tests <> " S3-dependent tests"
+      else System.IO.putStrLn $ "S3 credentials not found - skipping " <> show s3Tests <> " S3-dependent tests"
+    System.IO.putStrLn $ "To run S3 tests, set: TASKRUNNER_TEST_S3_ENDPOINT, TASKRUNNER_TEST_S3_ACCESS_KEY, TASKRUNNER_TEST_S3_SECRET_KEY"
+
+  when (skipSlow && slowTests > 0) $
+    System.IO.putStrLn $ "SKIP_SLOW_TESTS=1 - skipping " <> show slowTests <> " slow tests"
+
+  System.IO.putStrLn $ "Running " <> show runningTests <> "/" <> show totalTests <> " tests"
   pure $ Tasty.withResource (FakeGithubApi.start fakeGithubPort) FakeGithubApi.stop \fakeGithubServer ->
     testGroup "tests"
       [ goldenVsStringDiff
@@ -105,6 +129,9 @@ runTest fakeGithubServer source = do
                 , ("GITHUB_REPOSITORY_OWNER", "fakeowner")
                 , ("GITHUB_REPOSITORY", "fakerepo")
                 ] <>
+              mwhen options.quiet
+                [ ("TASKRUNNER_QUIET", "1")
+                ] <>
               s3ExtraEnv)
             , cwd = Just dir
             } \_ _ _ processHandle -> do
@@ -142,6 +169,7 @@ data Options = Options
   -- | Whether to provide GitHub app credentials in environment.
   -- If github status is disabled, taskrunner should work without them.
   , githubKeys :: Bool
+  , quiet :: Bool
   }
 
 instance Default Options where
@@ -150,6 +178,7 @@ instance Default Options where
     , toplevel = True
     , s3 = False
     , githubKeys = False
+    , quiet = False
     }
 
 getOptions :: Text -> Options
@@ -169,6 +198,9 @@ getOptions source = flip execState def $ go (lines source)
       ["#", "github", "keys"] -> do
         modify (\s -> s { githubKeys = True })
         go rest
+      ["#", "quiet"] -> do
+        modify (\s -> (s :: Options) { quiet = True })
+        go rest
       -- TODO: validate?
       _ ->
         -- stop iteration
@@ -213,3 +245,16 @@ maybeWithBucket Options{s3=True} block = do
 mwhen :: Monoid a => Bool -> a -> a
 mwhen True x = x
 mwhen False _ = mempty
+
+hasS3Directive :: FilePath -> IO Bool
+hasS3Directive file = do
+  content <- System.IO.readFile file
+  let options = getOptions (toText content)
+  pure options.s3
+
+hasS3Credentials :: IO Bool
+hasS3Credentials = do
+  endpoint <- lookupEnv "TASKRUNNER_TEST_S3_ENDPOINT"
+  accessKey <- lookupEnv "TASKRUNNER_TEST_S3_ACCESS_KEY"
+  secretKey <- lookupEnv "TASKRUNNER_TEST_S3_SECRET_KEY"
+  pure $ isJust endpoint && isJust accessKey && isJust secretKey

test/t/quiet-mode-failure.out

@@ -0,0 +1,4 @@
+-- output:
+[toplevel] stdout | This output should be shown because the command fails
+[toplevel] stdout | Second line of output
+-- exit code: 1

test/t/quiet-mode-failure.txt

@@ -0,0 +1,4 @@
+# quiet
+echo "This output should be shown because the command fails"
+echo "Second line of output"
+exit 1

test/t/quiet-mode-nested-child-fail.out

@@ -0,0 +1,2 @@
+-- output:
+[nested] stdout | Nested output before failure