acquiring-skill-lock

acquiring-skill-lock is a skill for Claude Code from Acendas/shipyard. It costs 16 tokens per session (1,449 once invoked), scanned A, original, MIT.

A project lock that records whether a planning or execution skill is currently using a project.

In plain words
What is it for?
Use it to acquire, release, check, or inspect the active planning and execution session for a project.
Why use it?
It prevents two terminals or sessions from changing the same project workflow at the same time. This reduces races between planning and implementation work.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions Claude Code.

Part of the shipyard plugin — 32 skills, 7 agents, 4 hooks shipped together

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 skills/acendas/shipyard/acquiring-skill-lock
Any agent
npx skills add Acendas/shipyard --skill acquiring-skill-lock
Clone the repo
git clone --depth 1 https://github.com/Acendas/shipyard

Made for: Claude Code.

Or install shipyard, the plugin that ships this one along with the rest of its 32 skills, 7 agents, 4 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for acquiring-skill-lock

README.md
[![agentmods](https://agentmods.dev/badge/skills/acendas/shipyard/acquiring-skill-lock.svg)](https://agentmods.dev/skills/acendas/shipyard/acquiring-skill-lock)
Your own site
<a href="https://agentmods.dev/skills/acendas/shipyard/acquiring-skill-lock"><img src="https://agentmods.dev/badge/skills/acendas/shipyard/acquiring-skill-lock.svg" alt="Measured on agentmods" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,449 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 5.1 $0.00016 $0.01449
Opus 5 $0.00008 $0.00724
Sonnet 5 $0.00003 $0.00290
Haiku 4.5 $0.00002 $0.00145

Measured 5d ago against content hash 09f316078016, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

acquiring-skill-lock 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 5d ago.

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.

plugins/shipyard/skills/acquiring-skill-lock/SKILL.md · 71 lines

How it starts

The opening of the file, as written. The whole thing — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Acquiring a Skill Lock

Shipyard tracks one active skill per project at a time, in two lock files under the data dir:

  • <SHIPYARD_DATA>/.active-session.json — held by planning skills (/ship-discuss, /ship-sprint, /ship-quick's planning phase).
  • <SHIPYARD_DATA>/.active-execution.json — held by execution skills (/ship-execute, /ship-review, /ship-quick's execution phase).

These are mutually exclusive: a planning session in one terminal must release before an execution skill starts in another, and vice versa. The lock is what prevents two terminals from racing on the same sprint.

v3.7.0: both files are CLI-owned. bin/skill-lock.mjs (shipyard-data lock acquire|release|check|status) is the single writer. No skill body Reads or Writes these files directly anymore — the PreToolUse hook denies any model Write/Edit to either basename, same as the pipeline cursors. Run the CLI, act on its exit code and JSON stdout line, and echo its stderr text (block message or recovery note) verbatim to the user.

The Lock Shape (for reference — never hand-construct this)

A held lock:

{
  "skill": "ship-execute",
  "sprint": "sprint-007",
  "wave": 2,
  "started": "2026-05-08T14:23:00Z",
  "session_id": "01HXY1Z2A3B4C5D6E7F8G9H0J1",
  "cleared": null,
  "depth": 1
}

A released (soft-deleted) lock: {"skill": null, "cleared": "<iso>"} — the file is never unlinked, only overwritten in place.

depth replaces the old ad-hoc "same-session re-entry, don't re-acquire" prose rule: lock acquire on an already-mine lock increments depth instead of duplicating the acquire, and lock release decrements it — the lock only fully releases (writes the sentinel) when depth reaches 0. This makes nested re-entry (e.g. /ship-execute invoking /ship-status for a pre-flight check) structurally safe without every skill having to reason about "am I the outermost caller."

compaction_count (a pre-v3.7.0 field) is gone — it was initialized but never incremented once the post-compact hook that used to bump it was retired, so the /ship-execute warning gated on it never fired. Do not resurrect it; a future context-pressure mechanism should be a new field, not this one.

Read the full file on GitHub · 71 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. 5d ago First seen · 71 lines · 16 tokens per session scan A 09f316078016

Subscribe to this mod's changes

acquiring-skill-lock is a skill published in the GitHub repository Acendas/shipyard (2 stars, last pushed 24d ago), licensed MIT. It adds 16 tokens to every session and 1,449 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 2026-08-31.

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