OPSX: Sync

A command that applies the differences in a selected change specification to the project's main specifications. It merges the changes into existing requirements instead of copying the entire change.

In plain words
What is it for?
Use it after a specification change to update the corresponding main requirements, such as adding a new scenario to an existing requirement.
Why use it?
It keeps the main specifications up to date while preserving their existing structure. It also avoids applying the wrong change by requiring an explicit selection when the change is unclear.

Command for Claude Code

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/fonoster/fonoster/sync
Clone the repo
git clone --depth 1 https://github.com/fonoster/fonoster

Made for: Claude Code.

Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,055 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00014 $0.01055
Opus 5 $0.00007 $0.00528
Sonnet 5 $0.00003 $0.00211
Haiku 4.5 $0.00001 $0.00105

Measured yesterday against content hash e97847e845c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

OPSX: Sync scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

.claude/commands/opsx/sync.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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).

Input: Optionally specify a change name after /opsx:sync (e.g., /opsx:sync add-auth). If omitted, check if it can be inferred from conversation context. If vague or ambiguous you MUST prompt for available changes.

Steps

  1. If no change name provided, prompt for selection

    Run openspec list --json to get available changes. Use the AskUserQuestion tool to let the user select.

    Show changes that have delta specs (under specs/ directory).

    IMPORTANT: Do NOT guess or auto-select a change. Always let the user choose.

  2. Resolve change context

    Run:

    openspec status --change "<name>" --json
    

    If status reports actionContext.mode: "workspace-planning", explain that workspace spec sync is not supported in this slice and STOP. Do not fall back to repo-local paths or edit linked repos.

  3. Find delta specs

    Use artifactPaths.specs.existingOutputPaths from the status JSON as the list of delta spec files.

    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.

  4. For each delta spec, apply changes to main specs

    For each repo-local capability delta spec path returned by the CLI:

    a. Read the delta spec to understand the intended changes

    b. Read the main spec at openspec/specs/<capability>/spec.md (may not exist yet)

    c. Apply changes intelligently:

    ADDED Requirements:

    • If requirement doesn't exist in main spec → add it
    • If requirement already exists → update it to match (treat as implicit MODIFIED)

    MODIFIED Requirements:

    • Find the requirement in main spec
    • Apply the changes - this can be:
      • Adding new scenarios (don't need to copy existing ones)
      • Modifying existing scenarios
      • Changing the requirement description
    • Preserve scenarios/content not mentioned in the delta

    REMOVED Requirements:

    • Remove the entire requirement block from main spec

    RENAMED Requirements:

    • Find the FROM requirement, rename to TO

    d. Create new main spec if capability doesn't exist yet:

    • Create openspec/specs/<capability>/spec.md
    • Add Purpose section (can be brief, mark as TBD)
    • Add Requirements section with the ADDED requirements
  5. Show summary

    After applying all changes, summarize:

    • Which capabilities were updated
    • What changes were made (requirements added/modified/removed/renamed)

Delta Spec Format Reference

## 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
#### 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`

Key Principle: Intelligent Merging

Unlike programmatic merging, you can apply partial updates:

  • To add a scenario, just include that scenario under MODIFIED - don't copy existing scenarios
  • The delta represents intent, not a wholesale replacement
  • Use your judgment to merge changes sensibly

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.

Read the full file on GitHub · 144 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 144 lines · 14 tokens per session scan A e97847e845c8

Subscribe to this mod's changes

OPSX: Sync is a command published in the GitHub repository fonoster/fonoster (8,094 stars, last pushed 6d ago), licensed MIT. It adds 14 tokens to every session and 1,055 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.