A synchronization command for refreshing two benchmark sandboxes with the latest local companion extension and the checked-in SpecKit templates. It copies the canonical example project into both variant folders and prepares them for testing.

Use it after changing the extension, updating the SpecKit command-line tool, or setting up the benchmark on a new machine.

It prevents benchmark runs from using outdated code or templates. This keeps comparisons aligned with the current project version.

How alfredoperez/speckit-companion configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to alfredoperez/speckit-companion. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/alfredoperez/speckit-companion/main/.claude/commands/bench-sync.md

Clone the repo

git clone --depth 1 https://github.com/alfredoperez/speckit-companion

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/alfredoperez/speckit-companion/bench-sync/github.svg)](https://agentmods.dev/commands/alfredoperez/speckit-companion/bench-sync)

Your own site

<a href="https://agentmods.dev/commands/alfredoperez/speckit-companion/bench-sync"><img src="https://agentmods.dev/badge/commands/alfredoperez/speckit-companion/bench-sync/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/commands/alfredoperez/speckit-companion/bench-sync"><img src="https://agentmods.dev/badge/commands/alfredoperez/speckit-companion/bench-sync.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 640 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00013	$0.00640
Opus 5.5	$0.00005	$0.00256
Sonnet 5.5	$0.00003	$0.00128
Haiku 4.5	$0.00001	$0.00064

Measured 19d ago against content hash fd49c79a2736, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

bench-sync scanned grade B with 1 finding 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 19d 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.

Unrestricted tool accessmediumExcessive agency

A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.

allowed-tools: Bash(. .claude/sandboxes-env.sh:*), Bash(node "$SANDBOXES_REPO"/bench/sync-templates.mjs:*), Bash(node "$SANDBOXES_REPO"/bench/run-all.mjs:*), Bash(specify:*), Bash(uv tool:*), Bash(npm run compile:*)

.claude/commands/bench-sync.md · 40 lines

How it starts

The opening of the file, as written. The whole thing — 40 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Your task

Bake the bench cells so a round measures current tooling. The harness lives in the bench/ folder of the sibling speckit-sandboxes repo; the app it measures lives in conduit. Nothing it writes lands in this repo.

Paths

Shell state does not persist between Bash calls, so start each one with . .claude/sandboxes-env.sh. It sets $SANDBOXES_REPO, the sibling speckit-sandboxes checkout, whose bench/ folder is the harness.

1. Compile the extension first

The driver dispatches the same per-step preamble the GUI does, imported from dist/ai-providers/promptPreamble.js. Build it:

npm run compile

2. Bake

node "$SANDBOXES_REPO"/bench/sync-templates.mjs --sizes easy,medium,hard,oversized

Defaults are --speckit latest --ext latest, which is what a measured round wants:

--speckit latest installs the spec-kit CLI from GitHub source (uv tool install specify-cli --from git+https://github.com/github/spec-kit.git --force) — the only build that carries specify extension. --speckit keep leaves whatever is installed.
--ext latest installs the Companion spec-kit extension from the rolling companion-latest release asset. --ext code installs from this checkout's apps/speckit-extension/ with --dev (use it to measure unreleased work). --ext <tag> pins an archived release.

The bake reflinks the app clone per cell (instant, node_modules included — no dependency install), runs specify init, arms each cell for its arm, tags a git baseline, and fails loudly if any cell file mentions the bench. It records the spec-kit CLI version, the spec-kit extension version and the Companion version into cells.json, and every result row carries all three.

If the app clone is missing, the script prints the one-time clone command. Run it once per laptop.

3. Report

Print the three versions the bake recorded and confirm the cell count. Say which arm each letter carries only if the user asks — the letters are opaque on purpose, and node "$SANDBOXES_REPO"/bench/run-all.mjs --dry-run prints the table when it is wanted.

Read the full file on GitHub · 40 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.

19d ago Changed · +4 lines fd49c79a2736
1mo ago Changed 1b89d216611c
1mo ago Changed · +3 lines · -10 tokens per session scan A → B 411fe06f6ec2
1mo ago First seen · 33 lines · 23 tokens per session scan A 4460d504af85

Subscribe to this mod's changes

bench-sync is a command published in the GitHub repository alfredoperez/speckit-companion (99 stars, last pushed 6d ago), licensed MIT. It adds 13 tokens to every session and 640 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 1 finding (unrestricted tool access). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Claude Code Planning TypeScript ai-tools developer-tools spec-driven-development vscode-extension

speckit-companion: Command for Claude Code

Borrowing it

Wrote this? Show the measurements

What it costs to keep this loaded

Grade B, and why

Unrestricted tool accessmediumExcessive agency

How it starts

Your task

Paths

1. Compile the extension first

2. Bake

3. Report

What this file has done since we first saw it

Other commands, from other repositories

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explain

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peachflow:init