${specName} validation failed - duplicate requirement in MOD

Error message

${specName} validation failed - duplicate requirement in MODIFIED for header "### Requirement: ${mod.name}"

What it means

Error "${specName} validation failed - duplicate requirement in MODIFIED for header "### Requirement: ${mod.name}"" thrown in Fission-AI/OpenSpec.

Source

Thrown at src/core/specs-apply.ts:212

  const plan = parseDeltaSpec(changeContent);
  const specName = update.id;

  // Pre-validate duplicates within sections
  const addedNames = new Set<string>();
  for (const add of plan.added) {
    const name = normalizeRequirementName(add.name);
    if (addedNames.has(name)) {
      throw new Error(
        `${specName} validation failed - duplicate requirement in ADDED for header "### Requirement: ${add.name}"`
      );
    }
    addedNames.add(name);
  }
  const modifiedNames = new Set<string>();
  for (const mod of plan.modified) {
    const name = normalizeRequirementName(mod.name);
    if (modifiedNames.has(name)) {
      throw new Error(
        `${specName} validation failed - duplicate requirement in MODIFIED for header "### Requirement: ${mod.name}"`
      );
    }
    modifiedNames.add(name);
  }
  const removedNamesSet = new Set<string>();
  for (const rem of plan.removed) {
    const name = normalizeRequirementName(rem);
    if (removedNamesSet.has(name)) {
      throw new Error(
        `${specName} validation failed - duplicate requirement in REMOVED for header "### Requirement: ${rem}"`
      );
    }
    removedNamesSet.add(name);
  }
  const renamedFromSet = new Set<string>();
  const renamedToSet = new Set<string>();
  for (const { from, to } of plan.renamed) {

View on GitHub (pinned to 6926ccb18a)

When it happens

Trigger: Thrown at src/core/specs-apply.ts:212 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/1449ddceb39878b6. Report an issue: GitHub.