fix: read host JSON from stdin - #1010

Summary

Allow all host-authored JSON inputs (--plan, --competitors-plan, --judgments, and --angles) to use - for stdin. Update the agent skill templates to use quoted heredocs instead of temporary files with rm -f cleanup traps, which Codex can reject before the research command executes.

Inline JSON and existing JSON file paths remain supported.

Testing

• uv run pytest — 4,007 passed, 6 skipped, 48 subtests passed
• Added or updated tests that would catch a regression, including end-to-end stdin coverage for all four JSON inputs and a host-contract check that rejects reintroducing cleanup traps

Changelog

• Added changelog.d/+stdin-json-inputs.fixed.md (types: added, changed, fixed, removed, deprecated, security)
• Skip changelog — chore/internal only (also add the skip-changelog label)

Agent disclosure

AI review

Codex reviewed backward compatibility for inline and file-backed JSON, error handling for invalid stdin JSON, shell quoting in every documented heredoc, and the full three-leg discovery protocol. The review identified indentation drift in one new fixture, which was corrected before the full test run. git diff --check is clean.

Security

Stdin content follows the same json.loads parsing and schema validation as existing inline/file inputs. The quoted heredocs suppress shell interpolation, and removing temporary files also removes the associated cleanup command and filesystem race surface. No auth, secrets, or dependencies changed.

Notes

The generic Codex skill validator was also attempted, but this repository's existing SKILL.md frontmatter contains supported project metadata fields that the generic validator does not accept. The repository's own complete test suite and skill contract tests pass.

Relationship to this change

• None
• Yes — disclosure:

Related issues

N/A — observed directly in Codex Desktop when the local command safety layer rejected the mandatory rm -f cleanup trap before execution.