skills/openspec-sync-specs/SKILL.md
Sync delta specs from a change to main specs.
This is an agent-driven operation - you will read delta specs and directly edit main specs to apply the changes. This allows intelligent merging (e.g., adding a scenario without copying the entire requirement).
Store selection: If the user names a store (a store is a standalone OpenSpec repo registered on this machine) or the work lives in one, run openspec store list --json to discover registered store ids, then pass --store <id> on the commands that read or write specs and changes (new change, status, instructions, list, show, validate, archive, doctor, context, view). Once selected, treat --store <id> as sticky for the rest of the workflow. Every unscoped example of those commands below is shorthand: before running it, append the flag. For example, run openspec status --change "<name>" --json --store "<id>", not the unscoped form shown below. Other commands do not take the flag. Hints printed by commands already carry the flag; keep it on follow-ups. Without a store, commands act on the nearest local openspec/ root.
<capability-path> is the spec directory relative to specs/ (for example, user-auth or identity/user-auth). Preserve the full path from each delta spec when resolving its main spec.
Input: Optionally specify a change name. If omitted, check if it can be inferred from conversation context. If vague or ambiguous you MUST prompt for available changes.
Steps
Select the change
If a name is provided, use it. Otherwise:
openspec list --json to get available changes and ask the user to select oneWhen prompting, show changes that have delta specs (under specs/ directory).
Always announce: "Using change: <name>" and how to override (e.g., /openspec-sync-specs <other>).
Resolve change context
Run:
openspec status --change "<name>" --json
The JSON includes planningHome.root. Main specs live under <planningHome.root>/openspec/specs/ — use that (store-aware) root for every main-spec path below, not a hardcoded repo path. When a store is selected it points at the store, not the current repository.
Find delta specs
Use artifactPaths.specs.existingOutputPaths from the status JSON as the
only source of delta spec paths. If the specs entry is missing or
existingOutputPaths is empty, report that there are no delta specs to sync,
do not infer them from other artifacts, and stop without requesting artifact
instructions or writing a main spec.
Sync every path in existingOutputPaths unless the caller narrowed the set.
A caller narrows it by naming an explicit list of complete entries from
existingOutputPaths — copy those absolute values verbatim. Archive does
this inline, and a user can too (for example, by selecting the entry ending
in /specs/billing/invoices/spec.md).
Then sync only the named paths and leave the remaining delta specs untouched:
bulk archive excludes a delta whose implementation it could not find, and
syncing it anyway would write a main spec the caller deliberately withheld.
Carry that narrowed selection through step 4; never widen it back to the full
list. If a named path is not in existingOutputPaths, do not sync it —
report it and stop, rather than dropping it silently. If the named list is
empty, report that there is nothing to sync and stop without writing a main
spec.
Each delta spec file contains sections like:
## ADDED Requirements - New requirements to add## MODIFIED Requirements - Changes to existing requirements## REMOVED Requirements - Requirements to remove## RENAMED Requirements - Requirements to rename (FROM:/TO: format)If no delta specs found, inform user and stop.
For each delta spec, apply changes to main specs
Before the first main-spec write, obtain one current specs-rule snapshot:
openspec instructions specs --change "<name>" --json, reuse it and do not
fetch the same instructions again.rules means no artifact rules are configured
and the existing semantic merge continues.Apply returned rules only to the content and form of the main specs produced
by this merge. Artifact rules are not operation guidance and cannot change
selected roots, delta paths, CLI checks, or workflow steps. Use their text as
constraints without copying it verbatim into a main spec or summary.
For each capability delta spec path selected in step 3 — the full existingOutputPaths list, or the narrowed subset when a caller supplied one (these may belong to a selected store, not the repo):
a. Read the delta spec to understand the intended changes
b. Read the main spec at <planningHome.root>/openspec/specs/<capability-path>/spec.md (may not exist yet)
c. Apply changes intelligently:
ADDED Requirements:
MODIFIED Requirements:
REMOVED Requirements:
spec.md - and the directory once
nothing else is left in it - only when ALL of these hold:
## Purpose);.openspec.yaml declares retire_capabilities: true;spec.md resolves inside the real specs root (do not follow a
capability-directory symlink to delete an external file).
If removing the selected requirements would leave no requirement blocks and
any retirement condition is not satisfied, do not modify the main spec. Stop
the sync for that capability, report the blocking condition, and tell the user
how to resolve it. Never write or leave an empty ## Requirements section.
When only the marker is missing, say that too - it is the one thing the user
can add to make the retirement go through.## Purpose; any other section blocks
retirement. Name Purpose when you report the retirement. Include a pasteable
git checkout only when the spec lived in the caller's checkout;
otherwise give checkout-scoped recovery guidance.RENAMED Requirements:
## Purpose in the delta:
openspec archive does; it warns and moves on)d. Create new main spec if capability doesn't exist yet:
<planningHome.root>/openspec/specs/<capability-path>/spec.md## Purpose body verbatim when it has one
(this is what openspec archive does); only write a brief TBD placeholder when it does notValidate updated main specs
Run openspec validate --specs with the same selected-root flags used earlier.
If validation fails, report the problems and do not claim the sync succeeded.
Show summary
After applying all changes, summarize:
spec.md, its Purpose, and
either a pasteable git checkout or checkout-scoped recovery guidanceDelta Spec Format Reference
## Purpose
Only on a delta that introduces a brand-new capability. Seeds the new main spec.
## ADDED Requirements
### Requirement: New Feature
The system SHALL do something new.
#### Scenario: Basic case
- **WHEN** user does X
- **THEN** system does Y
## MODIFIED Requirements
### Requirement: Existing Feature
The system SHALL keep doing the existing thing, now also handling A.
#### Scenario: Scenario the main spec already has
- **WHEN** user does X
- **THEN** system does Y
#### Scenario: New scenario to add
- **WHEN** user does A
- **THEN** system does B
## REMOVED Requirements
### Requirement: Deprecated Feature
## RENAMED Requirements
- FROM: `### Requirement: Old Name`
- TO: `### Requirement: New Name`
Main Spec Format Reference
Main specs are what the delta merges INTO. They must never contain delta operation headers (## ADDED/MODIFIED/REMOVED/RENAMED Requirements) - after syncing, every requirement lives under a single ## Requirements section:
# <capability> Specification
## Purpose
Short description of what this capability does and why it exists.
## Requirements
### Requirement: New Feature
The system SHALL do something new.
#### Scenario: Basic case
- **WHEN** user does X
- **THEN** system does Y
Key Principle: Intelligent Merging
Unlike programmatic merging, you merge rather than overwrite:
openspec validate and openspec archive both reject one that drops a scenario the main spec still has.Output On Success
## Specs Synced: <change-name>
Updated main specs:
**<capability-1>**:
- Added requirement: "New Feature"
- Modified requirement: "Existing Feature" (added 1 scenario)
**<capability-2>**:
- Created new spec file
- Added requirement: "Another Feature"
Main specs are now updated. The change remains active - archive when implementation is complete.
Guardrails
artifactPaths.specs.existingOutputPaths; never infer delta specs from unrelated artifactsexistingOutputPaths; never widen it back to the full list