Fission-AI/OpenSpec · error

MODIFIED failed for header "### Requirement: " - header…

Error message

${specName} MODIFIED failed for header "### Requirement: ${mod.name}" - header mismatch in content

What it means

Thrown in buildUpdatedSpec during MODIFIED application: the requirement exists, but the first line of the modified block's raw text does not parse as a '### Requirement:' header or does not normalize to the same key as the block it replaces. The replacement block's own header is malformed or mismatched.

Solutions

1. Make the MODIFIED block start with '### Requirement: <same name>' as its first line
2. Ensure the header name matches the requirement being modified (modulo case/whitespace)

When it happens

Trigger: Thrown at src/core/specs-apply.ts:459 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Fission-AI/OpenSpec@6926ccb18a (2026-08-25). Data as JSON: /api/errors/6bccdef4422d750a. Report an issue: GitHub.

Appendix: source

Thrown at src/core/specs-apply.ts:459

      }
      continue;
    }
    nameToBlock.delete(key);
    removedApplied++;
  }

  // MODIFIED
  let modifiedApplied = 0;
  for (const mod of plan.modified) {
    const key = normalizeRequirementName(mod.name);
    const currentBlock = nameToBlock.get(key);
    if (!currentBlock) {
      throw new Error(`${specName} MODIFIED failed for header "### Requirement: ${mod.name}" - not found`);
    }
    // Replace block with provided raw (ensure header line matches key)
    const modHeaderMatch = mod.raw.split('\n')[0].match(/^###\s*Requirement:\s*(.+)\s*$/i);
    if (!modHeaderMatch || normalizeRequirementName(modHeaderMatch[1]) !== key) {
      throw new Error(
        `${specName} MODIFIED failed for header "### Requirement: ${mod.name}" - header mismatch in content`
      );
    }
    const missingScenarios = findMissingCurrentScenarios(currentBlock, mod);
    if (missingScenarios.length > 0) {
      throw new Error(
        `${specName} MODIFIED failed for header "### Requirement: ${mod.name}" - current spec contains scenario(s) not present in the modified block: ${missingScenarios.map(name => `"${name}"`).join(', ')}. Refresh the change spec before archiving to avoid dropping scenarios.`
      );
    }
    // Identical content means the modification was already synced to the
    // baseline (early-sync pattern) — count only real replacements, so a
    // fully synced change still takes the "already in sync" write skip
    // instead of churning normalization differences into the file.
    if (normalizeBlockRaw(currentBlock.raw) !== normalizeBlockRaw(mod.raw)) {
      modifiedApplied++;
    }
    nameToBlock.set(key, mod);
  }

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