Borrowing it
Nothing to install: this file belongs to a2aproject/a2a-tck. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/a2aproject/a2a-tck/main/.agents/skills/learn-requirement/SKILL.mdgit clone --depth 1 https://github.com/a2aproject/a2a-tckWrote 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/a2aproject/a2a-tck/learn-requirement)<a href="https://agentmods.dev/skills/a2aproject/a2a-tck/learn-requirement"><img src="https://agentmods.dev/badge/skills/a2aproject/a2a-tck/learn-requirement/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/a2aproject/a2a-tck/learn-requirement"><img src="https://agentmods.dev/badge/skills/a2aproject/a2a-tck/learn-requirement.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00063 | $0.01055 |
| Opus 5.5 | $0.00025 | $0.00422 |
| Sonnet 5.5 | $0.00013 | $0.00211 |
| Haiku 4.5 | $0.00006 | $0.00105 |
Grade A, and why
learn-requirement 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 2mo 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 — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Learn About a Requirement
Follow these steps to help the user understand a TCK requirement in depth.
Step 1: Identify the requirement
Ask the user for the requirement ID (e.g., CORE-SEND-001, GRPC-ERR-001, JSONRPC-SSE-001, HTTP_JSON-REST-001).
If the user describes a concept instead of an ID, search the requirement files to find matching requirements:
tck/requirements/core_operations.py — CORE-*
tck/requirements/binding_grpc.py — GRPC-*
tck/requirements/binding_jsonrpc.py — JSONRPC-*
tck/requirements/binding_http_json.py — HTTP_JSON-*
tck/requirements/data_model.py — data model requirements
tck/requirements/streaming.py — streaming requirements
tck/requirements/push_notifications.py — push notification requirements
tck/requirements/agent_card.py — agent card requirements
tck/requirements/auth.py — authentication requirements
tck/requirements/versioning.py — versioning requirements
tck/requirements/interop.py — interoperability requirements
Step 2: Read the requirement definition
Find and read the RequirementSpec entry for the requirement ID in the appropriate file under tck/requirements/.
Present the following fields to the user:
- ID — the requirement identifier
- Section — the spec section number
- Title — short description
- Level — MUST, SHOULD, or MAY
- Description — what the requirement says
- Operation — which A2A operation it applies to
- Expected behavior — what a compliant implementation should do
- Spec URL — convert the local
spec_urlto a GitHub link: readspecification/version.jsonforsourceUrl, replace/tree/with/blob/, replace trailing/specificationwith/docs, then append the filename and anchor fromspec_url - Tags — categorization tags
- Sample input — example request payload (if provided)
Step 3: Find the specification text
Read specification/specification.md and search for the section referenced by the requirement's section field. Present the relevant specification text so the user can see the normative language (MUST/SHOULD/MAY) in context.
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.
- 2mo ago First seen · 90 lines · 63 tokens per session scan A 599135accd98
learn-requirement is a skill published in the GitHub repository a2aproject/a2a-tck (56 stars, last pushed 8d ago), licensed Apache-2.0. It adds 63 tokens to every session and 1,055 once invoked, about $0.0003 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 2026-08-30.
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