CtrlK
BlogDocsLog inGet started
Tessl Logo

a2a-protocol

How agent-native apps discover, authenticate with, and call each other over A2A. Use when connecting one app to another, debugging a remote agent that won't authenticate, exposing skills to peers, or calling agents from scripts.

66

Quality

81%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide

SecuritybySnyk

Low

Low-risk findings worth noting

SKILL.md
Quality
Evals
Security

Quality

Content

71%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body is highly actionable with complete code examples and clear sequencing, but it is a long monolithic document with some repeated guardrail prose and no progressive disclosure into reference files. Splitting the type/method reference material into separate files would improve both conciseness and disclosure.

Suggestions

Move the 'All Types', 'JSON-RPC Methods', and 'Message Parts' reference tables into a separate references/ file and link to them one level deep, reducing the main body length.

Consolidate the repeated 'do not bypass A2A / fix A2A instead' guardrail into a single Rule statement to remove duplicated prose between the Rule and Calling sections.

Add an explicit feedback loop after the peer probe step: 'If reachable-but-unauthorized, rotate/regenerate the shared secret on the Team page and re-probe.'

DimensionReasoningScore

Conciseness

Dense and free of basic-concept padding, but the ~415-line body repeats its anti-bypass guardrail ('No workarounds when A2A feels flaky') across the Rule and Calling sections and could be tightened noticeably.

3 / 5

Actionability

Provides copy-paste-ready, executable TypeScript for callAgent(), invokeAgentAction(), and A2AClient plus concrete paths and probe endpoints covering the common calling patterns.

5 / 5

Workflow Clarity

Registration, authentication, and calling flows are clearly sequenced with a probe validation step, but explicit validate→fix→retry feedback loops for failed peer checks are implied rather than spelled out.

4 / 5

Progressive Disclosure

No bundle files exist and the document is a single monolithic ~415-line file with inline reference material (All Types, JSON-RPC Methods, Message Parts) that would be better split into one-level-deep referenced files.

3 / 5

Total

15

/

20

Passed

Description

92%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

The description is third-person, concrete, and pairs a clear capability statement with multiple natural 'Use when' triggers. It is near-exemplary; only minor trigger-term variations are missing.

DimensionReasoningScore

Specificity

Names the A2A domain and enumerates concrete actions — discover, authenticate with, call, debug a remote agent that won't authenticate, expose skills to peers, call agents from scripts — giving comprehensive coverage with no real gaps.

5 / 5

Completeness

Explicitly answers both what (discover, authenticate, call over A2A) and when via concrete 'Use when...' trigger clauses with multiple scenarios.

5 / 5

Trigger Term Quality

Natural trigger phrases users would say ('connecting one app to another', 'debugging a remote agent that won't authenticate', 'calling agents from scripts') are present, but a few natural variations (e.g. @-mention, which appears in the body) are omitted.

4 / 5

Distinctiveness Conflict Risk

A clear niche (agent-to-agent A2A delegation) with distinct triggers and minimal overlap risk against other skills.

5 / 5

Total

19

/

20

Passed

Validation

81%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation13 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

metadata_version

'metadata.version' is missing

Warning

metadata_field

'metadata' should map string keys to string values

Warning

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

13

/

16

Passed

Repository
BuilderIO/agent-native
Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.