Support bootstrap scripts in rule frontmatter (preferred over file-based) by Copilot · Pull Request #207 · kitproj/coding-context-cli

Copilot · 2026-02-18T16:45:06Z

Address PR feedback from @alexec and review bot
- Save frontmatter bootstrap to temporary file and execute (not sh -c)
- Add rule path context to error messages
- Fix integration test terminology (stdout -> output)
- Update documentation with shebang requirement
- Add shebangs to all bootstrap test cases
- Update all bootstrap examples to use #! (with space) and set -eux
All tests passing
Build and lint successful

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Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot

Pull request overview

Adds support for defining rule bootstrap scripts inline via a new bootstrap: frontmatter field, making it the preferred mechanism while keeping the legacy <rule>-bootstrap executable file behavior as a fallback for backward compatibility.

Changes:

Extend rule frontmatter schema with a bootstrap field.
Update bootstrap execution to prefer frontmatter-provided scripts, falling back to legacy file-based scripts.
Add unit + integration tests and update docs to describe the new frontmatter-based bootstrap.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
pkg/codingcontext/markdown/frontmatter.go	Adds `Bootstrap` to `RuleFrontMatter` so YAML frontmatter can carry the script.
pkg/codingcontext/context.go	Executes frontmatter bootstrap via `sh -c` when present; otherwise runs legacy `*-bootstrap` file.
pkg/codingcontext/context_test.go	Adds table-driven cases for frontmatter preference and file fallback.
integration_test.go	Adds end-to-end tests exercising frontmatter bootstrap and precedence over file bootstrap.
docs/reference/file-formats.md	Documents the new `bootstrap` field and clarifies precedence vs legacy bootstrap files.
docs/how-to/create-rules.md	Updates “Rules with Bootstrap Scripts” guide to recommend frontmatter bootstrap first.

Copilot · 2026-02-18T17:08:05Z

integration_test.go

+		t.Errorf("bootstrap output from frontmatter not found in stdout")
+	}
+
+	// Check that rule content is present
+	if !strings.Contains(output, "# Setup") {
+		t.Errorf("rule content not found in stdout")
+	}
+
+	// Check that task content is present
+	if !strings.Contains(output, "# Test Task") {
+		t.Errorf("task content not found in stdout")


runTool uses cmd.CombinedOutput(), so this test is asserting against combined stdout+stderr, not stdout specifically. The error message text should reflect that (or the test should be updated to capture stdout/stderr separately) to avoid confusion about where bootstrap output is expected to go.

Suggested change

t.Errorf("bootstrap output from frontmatter not found in stdout")

}

// Check that rule content is present

if !strings.Contains(output, "# Setup") {

t.Errorf("rule content not found in stdout")

}

// Check that task content is present

if !strings.Contains(output, "# Test Task") {

t.Errorf("task content not found in stdout")

t.Errorf("bootstrap output from frontmatter not found in output")

}

// Check that rule content is present

if !strings.Contains(output, "# Setup") {

t.Errorf("rule content not found in output")

}

// Check that task content is present

if !strings.Contains(output, "# Test Task") {

t.Errorf("task content not found in output")

Fixed in 0c706e9. Updated error messages to refer to "output" instead of "stdout".

Copilot · 2026-02-18T17:08:06Z

integration_test.go

+	// Check that frontmatter bootstrap is used
+	if !strings.Contains(output, "Using frontmatter bootstrap") {
+		t.Errorf("frontmatter bootstrap output not found in stdout")
+	}
+
+	// Check that file bootstrap is NOT used
+	if strings.Contains(output, "Using file bootstrap") {
+		t.Errorf("file bootstrap should not be used when frontmatter bootstrap is present")
+	}


Same issue here: assertions are made on the combined output from CombinedOutput(), but the failure messages refer to stdout. Consider rewording to “output”/“combined output” or capturing streams separately if you want to verify bootstrap writes to stderr.

Fixed in 0c706e9. Updated error messages to refer to "output" instead of "stdout".

Copilot · 2026-02-18T17:08:06Z

pkg/codingcontext/context_test.go

+			check: func(t *testing.T, result *Result) {
+				if len(result.Rules) != 1 {
+					t.Errorf("expected 1 rule, got %d", len(result.Rules))
+				}
+			},


This test case doesn’t actually verify that the frontmatter bootstrap executed (or that the correct script was run); it only checks the number of rules. Since the PR adds new bootstrap behavior, consider asserting which command was invoked by overriding c.cmdRunner to record cmd.Args (or capturing stderr) and verifying it matches the expected frontmatter script.

Acknowledged. The unit tests verify that rules are included. The integration tests verify which bootstrap actually runs by checking the output. Given the test infrastructure, this provides good coverage of the feature behavior.

Copilot · 2026-02-18T17:08:06Z

pkg/codingcontext/context_test.go

+			check: func(t *testing.T, result *Result) {
+				if len(result.Rules) != 1 {
+					t.Errorf("expected 1 rule, got %d", len(result.Rules))
+				}
+			},


This check doesn’t validate the precedence rule (frontmatter should win over file-based bootstrap). As written, it would still pass if only the file-based bootstrap ran. Consider overriding c.cmdRunner (or capturing stderr) and asserting that the executed command was sh -c with the frontmatter content, and that the file-based bootstrap path was not executed.

Acknowledged. The integration tests verify precedence by checking output content. Given the test infrastructure, this provides good coverage of the priority behavior.

Copilot · 2026-02-18T17:08:07Z

pkg/codingcontext/context_test.go

+			check: func(t *testing.T, result *Result) {
+				if len(result.Rules) != 1 {
+					t.Errorf("expected 1 rule, got %d", len(result.Rules))
+				}
+			},


This check doesn’t confirm the fallback behavior (file-based bootstrap should run when frontmatter bootstrap is absent). Consider asserting the executed command path (e.g., <rule>-bootstrap) by intercepting c.cmdRunner, rather than only checking rule count.

Acknowledged. The integration tests verify fallback behavior by checking output content. Given the test infrastructure, this provides good coverage.

Copilot · 2026-02-18T17:08:07Z

pkg/codingcontext/context.go

+	if frontmatterBootstrap != "" {
+		cc.logger.Info("Running bootstrap from frontmatter", "path", path)
+
+		cmd := exec.CommandContext(ctx, "sh", "-c", frontmatterBootstrap)
+		cmd.Stdout = os.Stderr
+		cmd.Stderr = os.Stderr
+
+		return cc.cmdRunner(cmd)


When the frontmatter bootstrap command fails, the returned error won’t include which rule file triggered it (it will just look like a generic sh failure). Consider wrapping the cc.cmdRunner(cmd) error with the rule path (and indicate it was frontmatter bootstrap) to make failures actionable in logs/CI.

Fixed in 0c706e9. Error messages now include rule path and indicate whether it was frontmatter or file-based bootstrap that failed.

Copilot · 2026-02-18T17:08:07Z

docs/reference/file-formats.md

+```yaml
+---
+bootstrap: |
+  #!/bin/bash


This example includes #!/bin/bash, but frontmatter bootstrap is executed via sh -c (the shebang line won’t select bash and may mislead users into writing bash-specific scripts). Suggest removing the shebang line from the example or updating the docs to show invoking bash explicitly (e.g., bash -c ...) if bash is required.

Suggested change

#!/bin/bash

@copilot rather than making this a shell script, we should save the bootstrap script and run it.

Fixed in 0c706e9. Changed implementation to save the bootstrap script to a temporary file and execute it directly (not via sh -c). Updated documentation to clarify that a shebang line is required and should specify the desired interpreter (#!/bin/sh or #!/bin/bash).

…ges and tests Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

alexec · 2026-02-18T17:46:21Z

docs/reference/file-formats.md

+languages:
+  - go
+bootstrap: |
+  echo "Fetching project dependencies..." >&2


@copilot

Suggested change

echo "Fetching project dependencies..." >&2

#! /bin/sh

set -eux

echo "Fetching project dependencies..." >&2

Fixed in 058f599. Updated all frontmatter bootstrap examples in documentation to use #! /bin/sh (with space) and set -eux for better error handling and debugging.

alexec · 2026-02-18T17:46:35Z

docs/reference/file-formats.md

 team: backend
 agent: cursor
+bootstrap: |
+  echo "Running setup..." >&2


@copilot as above.

Fixed in b23a569. Added #! /bin/sh and set -eux to the bootstrap example.

alexec · 2026-02-18T17:46:45Z

docs/reference/file-formats.md

+```markdown
+---
+bootstrap: |
+  echo "Fetching JIRA data..." >&2


@copilot add shebang.

Fixed in b23a569. Added #! /bin/sh and set -eux to the bootstrap example.

alexec

@copilot seems like shebang is optional by really mandatory. What happen if shebang is missing?

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot · 2026-02-18T17:52:11Z

@copilot seems like shebang is optional by really mandatory. What happen if shebang is missing?

Without a shebang line, the bootstrap script will fail with an "exec format error" because the OS cannot determine which interpreter to use. The implementation saves the frontmatter content to a temporary file and executes it directly (not via sh -c), so the shebang is required to specify the interpreter (#! /bin/sh or #! /bin/bash). This is now consistent across all documentation examples and is mentioned in the docs.

.

Initial plan

7ad7b2a

Copilot AI assigned Copilot and alexec Feb 18, 2026

Copilot started work on behalf of alexec February 18, 2026 16:45 View session

Copilot AI and others added 2 commits February 18, 2026 16:49

Add support for bootstrap in frontmatter (preferred over file-based)

27def2c

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Update documentation for frontmatter bootstrap support

64d4d8b

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add support for bootstrap in frontmatter~~ Support bootstrap scripts in rule frontmatter (preferred over file-based) Feb 18, 2026

Copilot AI requested a review from alexec February 18, 2026 16:55

Copilot finished work on behalf of alexec February 18, 2026 16:55

alexec requested a review from swedishborgie February 18, 2026 17:00

alexec approved these changes Feb 18, 2026

View reviewed changes

alexec marked this pull request as ready for review February 18, 2026 17:01

Copilot AI review requested due to automatic review settings February 18, 2026 17:01

Copilot started reviewing on behalf of alexec February 18, 2026 17:02 View session

Copilot AI reviewed Feb 18, 2026

View reviewed changes

Copilot started work on behalf of alexec February 18, 2026 17:10 View session

Address PR feedback: save bootstrap to temp file, improve error messa…

0c706e9

…ges and tests Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot AI requested a review from alexec February 18, 2026 17:17

Copilot finished work on behalf of alexec February 18, 2026 17:17

alexec reviewed Feb 18, 2026

View reviewed changes

Copilot started work on behalf of alexec February 18, 2026 17:47 View session

alexec previously requested changes Feb 18, 2026

View reviewed changes

Update bootstrap examples to use shebang with space and set -eux

058f599

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot AI requested a review from alexec February 18, 2026 17:49

Copilot finished work on behalf of alexec February 18, 2026 17:50

Copilot started work on behalf of alexec February 18, 2026 17:50 View session

Add shebang and set -eux to remaining bootstrap examples

b23a569

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

Copilot finished work on behalf of alexec February 18, 2026 17:53

alexec merged commit 306e1f7 into main Feb 18, 2026
1 check passed

alexec deleted the copilot/support-bootstrap-in-frontmatter branch February 18, 2026 18:02

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