spar-act

spar-act is a skill for Claude Code, Codex from Jed-Tech/spar-kit. It costs 50 tokens per session (989 once invoked), scanned A, original, Apache-2.0.

An implementation workflow for carrying out an approved engineering plan. It follows the project's specification and plan while tracking tasks, validation, risks, and blockers.

In plain words
What is it for?
It is for executing the unchecked tasks in an active plan, in order where practical. It also uses the plan's validation strategy to check the resulting implementation.
Why use it?
It keeps coding aligned with agreed requirements and prevents silent changes to the project's intended scope. It stops when the work would require changing the specification or when a blocker needs a decision.

Skill for Claude CodeCodex

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/jed-tech/spar-kit/spar-act
Any agent
npx skills add Jed-Tech/spar-kit --skill spar-act
Clone the repo
git clone --depth 1 https://github.com/Jed-Tech/spar-kit

Made for: Claude Code, Codex.

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 spar-act

README.md
[![agentmods](https://agentmods.dev/badge/skills/jed-tech/spar-kit/spar-act.svg)](https://agentmods.dev/skills/jed-tech/spar-kit/spar-act)
Your own site
<a href="https://agentmods.dev/skills/jed-tech/spar-kit/spar-act"><img src="https://agentmods.dev/badge/skills/jed-tech/spar-kit/spar-act.svg" alt="Measured on agentmods" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 989 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 $0.00050 $0.00989
Opus 5 $0.00025 $0.00495
Sonnet 5 $0.00010 $0.00198
Haiku 4.5 $0.00005 $0.00099

Measured 4d ago against content hash e33df0d7064b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spar-act 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 4d 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.

install-root/skills/spar-act/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Act

Execute the approved plan.md while preserving the intent and boundaries in <change-name>_spec.md.

Act is implementation, not replanning. Refine execution details when needed, but do not change product intent, spec constraints, or accepted decisions without user approval.

Inputs

  • specs/active/<change-name>/<change-name>_spec.md
  • specs/active/<change-name>/plan.md
  • Optional notes or artifacts in the same folder, such as research.md
  • Relevant repository code and documentation

If the active spec or plan is missing, stop and use spar-plan first, or spar-specify if no spec exists.

Execution Context

Before changing files, read the spec and plan together.

  • Use spec Scope, Out of Scope, Constraints, Success Criteria, and Decisions as fixed implementation anchors.
  • Use plan Approach for the intended technical direction.
  • Use plan Execution Constraints as tactical guardrails.
  • Execute unchecked Tasks in order unless reordering is required for correctness.
  • Use plan Validation Strategy as the primary validation path.
  • Track plan Risks / Follow-ups while implementing and update them if new information materially changes them.

Execute Tasks

For each unchecked task:

  1. Understand the task, relevant spec anchors, and affected files.
  2. Implement the smallest coherent change that satisfies the task.
  3. Validate using the plan's Validation Strategy, plus targeted project checks when useful.
  4. Mark the task complete in plan.md only after validation is sufficient.

Keep plan.md accurate as work progresses. It is fine to split, clarify, or reorder tasks for correctness, but do not alter task intent in a way that changes the spec.

Research and Blockers

Use repo context first. When errors, APIs, or implementation details are unclear, use available MCP tools, official docs, vendor docs, or web search to understand the issue.

If a task fails:

  1. Investigate the cause.
  2. Fix obvious issues and retry once.
  3. If still blocked, stop, summarize what you tried, explain the blocker, offer concrete next-step options with a recommendation, and ask how to proceed.

Read the full file on GitHub · 131 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. 4d ago First seen · 131 lines · 50 tokens per session scan A e33df0d7064b

Subscribe to this mod's changes

spar-act is a skill published in the GitHub repository Jed-Tech/spar-kit (17 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 50 tokens to every session and 989 once invoked, about $0.0003 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.

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