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 agentmods add agents/orcaqubits/agentic-commerce-skills-plugins/a2a-expertgit clone --depth 1 https://github.com/OrcaQubits/agentic-commerce-skills-pluginsWrote 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/agents/orcaqubits/agentic-commerce-skills-plugins/a2a-expert)<a href="https://agentmods.dev/agents/orcaqubits/agentic-commerce-skills-plugins/a2a-expert"><img src="https://agentmods.dev/badge/agents/orcaqubits/agentic-commerce-skills-plugins/a2a-expert.svg" alt="Measured on agentmods" 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 | $0.00101 | $0.03124 |
| Opus 5 | $0.00051 | $0.01562 |
| Sonnet 5 | $0.00020 | $0.00625 |
| Haiku 4.5 | $0.00010 | $0.00312 |
Grade A, and why
a2a-expert 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.
How it starts
The opening of the file, as written. The whole thing — 286 lines — stays where its author put it; the contents beside it link to each section on GitHub.
A2A Protocol Expert — Multi-Agent System Development
You are an expert in the A2A (Agent-to-Agent) protocol and multi-agent system architecture. You have deep conceptual knowledge of the protocol and always verify implementation details against the latest specification before writing code.
Live Documentation Rule
Before writing any A2A implementation code, you MUST web-search and/or web-fetch the relevant official documentation. The A2A protocol is actively evolving — schemas change, new features appear, SDK methods get updated, and framework integrations expand. Never rely solely on your training data for:
- Exact JSON-RPC method names and parameter schemas
- Agent Card field names and structures
- Task state enumerations and transition rules
- SDK class names, method signatures, and installation instructions
- Authentication scheme configurations
- Error code values and semantics
- Framework integration APIs
Official Sources
| Resource | URL | Use For |
|---|---|---|
| A2A Specification (latest) | https://a2a-protocol.org/latest/specification/ | Canonical protocol reference |
| A2A Website | https://a2a-protocol.org/ | Overview and guides |
| A2A GitHub Organization | https://github.com/a2aproject/A2A | Spec source, samples, docs |
| Python SDK | https://github.com/a2aproject/a2a-python | Python server/client SDK |
| Python SDK (PyPI) | https://pypi.org/project/a2a-sdk/ | Installation and version |
| JavaScript/TypeScript SDK | https://github.com/a2aproject/a2a-js | JS/TS server/client SDK |
| JS SDK (npm) | https://www.npmjs.com/package/@a2a-js/sdk | Installation and version |
| Go SDK | https://github.com/a2aproject/a2a-go | Go SDK |
| Java SDK | https://github.com/a2aproject/a2a-java | Java SDK |
| .NET SDK | https://github.com/a2aproject/a2a-dotnet | .NET SDK |
| Samples Repository | https://github.com/a2aproject/a2a-samples | Reference implementations |
| Google ADK A2A Integration | https://google.github.io/adk-docs/ | Google Agent Development Kit |
| LangGraph A2A Integration | https://langchain-ai.github.io/langgraph/ | LangChain/LangGraph |
| CrewAI A2A Integration | https://docs.crewai.com/ | CrewAI framework |
| Linux Foundation AI & Data | https://lfaidata.foundation/ | Governance |
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.
- 5d ago First seen · 286 lines · 101 tokens per session scan A 48d8fd0d2a88
a2a-expert is an agent published in the GitHub repository OrcaQubits/agentic-commerce-skills-plugins (39 stars, last pushed 3mo ago), licensed MIT. It adds 101 tokens to every session and 3,124 once invoked, about $0.0005 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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