Summary

While playing around I found that no matter what happens the first prompt from Prometheus to Momus always results in a rejection because of content wrapping the plan path. I also found after every reviewed loop prometheus will forget about the rejection again, this means there are repeat "useless" calls to Momus. Fix the planning workflow where Momus (Plan Reviewer) rejects execution due to strict input format validation when the incoming string contains wrapper text or system directives injected by Prometheus task tools.

Problem

When Prometheus calls task tools (sisyphus_task, task, call_omo_agent), the prometheus-md-only hook appends a multi-line system directive block (PLANNING_CONSULT_WARNING) to the tool prompt. This means Momus routinely receives non-path text even when Prometheus tries to pass only a path.

On top of that it seems that Prometheus will occasionally forget its directive on how to communicate with Prometheus and begin appending soft phrases around the file path again.

The original Momus prompt had a strict validation rule: "reject if any additional words exist beyond the file path." This caused valid invocations like Please review: .sisyphus/plans/issue-623.md (with or without the injected system directive block) to be rejected, blocking plan reviews.

Solution Approach

• Momus should be liberal in what it accepts: extract a plan file path from noisy input (including appended system directive blocks) and proceed.
• Prometheus should be conservative in what it sends: avoid adding additional conversational wrappers beyond the path (though system hooks may still append directives).

Changes

Momus Agent (src/agents/momus.ts)

• Replaced strict input validation with an extraction algorithm:

  1. Ignore injected system directive blocks, especially [SYSTEM DIRECTIVE - READ-ONLY PLANNING CONSULTATION] (remove the whole block, including --- separators and bullet lines)
  2. Strip other system directive wrappers (bracket-style blocks and XML-style tags)
  3. Strip markdown wrappers around paths (code fences and inline backticks)
  4. Extract plan paths by finding all substrings containing .sisyphus/plans/ and ending in .md
  5. If exactly 1 match → ACCEPT and proceed
  6. If 0 matches → REJECT with "no plan path found"
  7. If 2+ matches → REJECT with "ambiguous: multiple plan paths"

• Updated examples: Moved Please review .sisyphus/plans/plan.md from INVALID to VALID

• Updated rejection messages: Include specific reason (Reason: no plan path found or Reason: multiple plan paths found)

Prometheus Agent (src/agents/prometheus-prompt.ts)

• Added explicit "MOMUS INVOCATION RULE": When invoking Momus, provide ONLY the file path string as the prompt
• Clarified: Do NOT wrap in explanations, markdown, or conversational text (system hooks may append directives, which is expected)

Test Coverage (src/agents/momus.test.ts, src/agents/prometheus-prompt.test.ts)

• Added prompt policy tests that verify the new behavior requirements
• Tests use stable anchor strings rather than brittle full-text matching
• Follow TDD workflow: tests added first (RED), prompts updated (GREEN)

Before:

• Input: Please review: .sisyphus/plans/issue-623.md → ❌ I REJECT (Input Format Validation)
• Input: .sisyphus/plans/plan.md with appended [SYSTEM DIRECTIVE...] block → ❌ Rejected

After:

• Input: Please review: .sisyphus/plans/issue-623.md → ✅ Extracts path, proceeds to review
• Input: .sisyphus/plans/plan.md with appended [SYSTEM DIRECTIVE...] block → ✅ Strips directive block, extracts path, proceeds

Testing

bun test src/agents/momus.test.ts
bun test src/agents/prometheus-prompt.test.ts
bun test

• 4 new tests in momus.test.ts (prompt policy requirements)
• 2 new tests in prometheus-prompt.test.ts (invocation policy)
• All tests pass
• Manual verification:
  • Static analysis of prompt content confirms extraction algorithm and policy changes
  • Prompting Sisyphus to prompt Momus, replicating several prompt and tracking which elicits a response and which gets a rejection:

Test Results

Related Issues

Summary by cubic

Fixes false rejections when Prometheus passes plan paths to Momus by relaxing Momus input validation and tightening Prometheus’s Momus calls. This unblocks plan reviews and cuts repeated calls.

• Bug Fixes
  • Momus: replace strict “path-only” check with path extraction that ignores system directive blocks and wrappers; accept exactly one .sisyphus/plans/*.md; reject none/multiple with clear reasons.
  • Prometheus: add rule to send only the file path (no markdown or chatter); system hook directives are expected.
  • Tests: add prompt policy tests for both agents to lock this behavior.

^{Written for commit 49555ca. Summary will update on new commits.}