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.
npx skills add firstintent/a2a-bridge --skill parallelgit clone --depth 1 https://github.com/firstintent/a2a-bridgeWrote 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.
[](https://agentmods.dev/skills/firstintent/a2a-bridge/parallel)<a href="https://agentmods.dev/skills/firstintent/a2a-bridge/parallel"><img src="https://agentmods.dev/badge/skills/firstintent/a2a-bridge/parallel/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.
<a href="https://agentmods.dev/skills/firstintent/a2a-bridge/parallel"><img src="https://agentmods.dev/badge/skills/firstintent/a2a-bridge/parallel.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00043 | $0.01203 |
| Opus 5.5 | $0.00017 | $0.00481 |
| Sonnet 5.5 | $0.00009 | $0.00241 |
| Haiku 4.5 | $0.00004 | $0.00120 |
Grade A, and why
parallel 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 133 lines — stays where its author put it; the contents beside it link to each section on GitHub.
parallel — spawn N independent peers, merge when they finish
The only safe multi-agent parallel pattern: carve the work into subtasks that do not depend on each other's outputs, send each to a peer, await all of them, then merge. If any subtask depends on another's result, this pattern degrades to sequential with extra steps and should not be used.
When to use
- Subtasks are independent by construction — different files, different modules, different investigations, different doc pages.
- Each subtask's output is stable regardless of the others' outcomes.
- Wall-clock latency matters enough to justify N× the token cost. (The equivalent sequential run costs 1× tokens; parallel costs N× and only saves time.)
When NOT to use
- Subtasks share context or build on each other's output. Merge loses fidelity; sequential with the real output is better.
- The "independence" is by job title (planner / implementer / tester / reviewer). This is sequential pretending to be parallel and almost always underperforms one session with the same tools.
- One of the subtasks would be cheap enough to inline. Parallel overhead only pays off when every branch is substantial.
Protocol
Spawn one message/stream call per subtask. Each call gets its own
contextId so replies do not cross wires; a2a-bridge's RoomRouter
(Phase 4) isolates them end-to-end. Then await every SSE stream to
its terminal status-update.final === true and merge.
┌─ subtask A ─────────► peer 1 ─► artifact-update A ─► final A ┐
├─ subtask B ─────────► peer 2 ─► artifact-update B ─► final B ┤─► merge
└─ subtask C ─────────► peer 3 ─► artifact-update C ─► final C ┘
return_format per branch is a caller choice:
"full"when each branch's raw output matters to the merge."summary"when only a conclusion per branch matters (seeskills/context-protect/)."verdict"when each branch is a check (seeskills/verify/); merge ispassonly when all branches returnpass.
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.
- 1mo ago First seen · 133 lines · 43 tokens per session scan A 0a1af6d839d4
parallel is a skill published in the GitHub repository firstintent/a2a-bridge (9 stars, last pushed 6mo ago), licensed MIT. It adds 43 tokens to every session and 1,203 once invoked, about $0.0002 per session on Opus 5.5. 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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