New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

A2a Protocol

by BuilderIO in BuilderIO/agent-native

How agent-native apps discover, authenticate with, and call each other over A2A.

No licenceAuto-check passedDevelopment

Install A2a Protocol

skills CLI
$ npx skills add BuilderIO/agent-native --skill a2a-protocol -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install BuilderIO/agent-native a2a-protocol --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/BuilderIO/agent-native.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/a2a-protocol .claude/skills/a2a-protocol && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
a2a-protocol
GitHub stars
7.1k
Token cost
~5.7k tokens
SKILL.md length
2,605 words
Files
1
Skills in repo
102
Repo updated
First seen
Licence
None found

At a glance

How agent-native apps discover, authenticate with, and call each other over A2A.

  • Works in 2 steps: B is registered on A as a… → A and B share a secret, so A's signed…
  • Connecting one app to another
  • SKILL.md covers Rule, A2A is already mounted, Registering a remote agent and Authentication, plus 9 more sections
  • Needs A2A_SECRET and ANALYTICS_A2A_TOKEN

What it does

A2a Protocol is an agent skill from BuilderIO/agent-native. 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.

Its SKILL.md is about 5.7k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development. It works with Agent2Agent Protocol. The repository describes itself as: A framework for building agentic apps.

When your agent uses it

  • Connecting one app to another
  • Debugging a remote agent that wont authenticate
  • Exposing skills to peers
  • Calling agents from scripts

Example prompts

  • “/a2a-protocol”

Requirements

  • A credential in ANALYTICS_A2A_TOKEN
  • A credential in A2A_SECRET

Workflow steps

2 steps, taken from the first numbered list in SKILL.md.

  1. B is registered on A as a remote-agents/.json resource.
  2. A and B share a secret, so A's signed JWT verifies on B.

What it can do on your machine

Read from SKILL.md and the folder at commit e16da0c. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript and json).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • learn.microsoft.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names these keys or tokens, usually read from environment variables:

    • A2A_SECRET
    • ANALYTICS_A2A_TOKEN
    • ANTHROPIC_API_KEY

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

A2a Protocol loads about 5.7k tokens when it runs. Until then it costs about 60 tokens; SKILL.md has 2,605 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~60
When it runs · the whole SKILL.md, loaded when a task matches
~5.7k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 2,605 words (~5,690 tokens).

“Agents call other agents over A2A, a JSON-RPC protocol for discovery and delegation. Use it when work belongs to a different agent entirely — not the local agent chat.”

— opening of SKILL.md by BuilderIO
name
a2a-protocol
scope
dev
metadata.internal
true

Read the full SKILL.md on GitHub

Files

Just SKILL.md in .agents/skills/a2a-protocol of BuilderIO/agent-native.

Open the folder on GitHubat commit e16da0c

Compare with similar skills

A2a Protocol next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

A2a Protocol compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
A2a Protocol this skillBuilderIO/agent-native7.1k—~5.7kAutomated safety check: PassNone
Draw Imageai-sns/ai-sns338—~778Automated safety check: PassMIT
Update A2a Protoa2aproject/a2a-java504—~738Automated safety check: PassApache-2.0
A2a CLIa2aproject/a2a-cli152—~1.5kAutomated safety check: NotesApache-2.0
Fix Tck Issuea2aproject/a2a-java504—~2.9kAutomated safety check: PassApache-2.0
Release A2aa2aproject/a2a-java504—~2.3kAutomated safety check: PassApache-2.0

Similar skills

  • Draw Image

    ai-sns/ai-sns

    Generate an image from a text prompt using an OpenAI-compatible image generation API (gpt-image-1-mini or compatible).

    338 GitHub stars~778 tokensUpdated 2 mo ago
    Media & CreativeAuto-check passed

  • Update A2a Proto

    a2aproject/a2a-java

    Update the A2A Protobuf file (a2a.proto) when the A2A protocol specification changes.

    504 GitHub stars~738 tokensUpdated 2 days ago
    Backend & APIsAuto-check passed

  • A2a CLI

    a2aproject/a2a-cli

    Delegate work to A2A (Agent2Agent) agents from the command line with the a2a CLI (github.com/a2aproject/a2a-cli).

    152 GitHub stars~1.5k tokensUpdated 7 days ago
    Backend & APIsAuto-check: notes

  • Fix Tck Issue

    a2aproject/a2a-java

    Analyzes and fixes A2A Transport Compatibility Kit (TCK) issues by understanding the specification, reproducing the failure, implementing the fix, and validating it works.

    504 GitHub stars~2.9k tokensUpdated 2 days ago
    Backend & APIsAuto-check passed

  • Release A2a

    a2aproject/a2a-java

    Guide maintainers through the multi-step release process — version bump, CI verification, tagging, Maven Central deployment, SNAPSHOT bump, and versioned documentation.

    504 GitHub stars~2.3k tokensUpdated 2 days ago
    DevOps & CloudAuto-check passed

  • A2a Protocol

    agntcy/coffeeAgntcy

    A skill your agent uses when the user asks about A2A (Agent-to-Agent) protocol communication, OASF record formats, AGNTCY directory operations, agent card parsing, or dirctl CLI usage.

    112 GitHub stars~1k tokensUpdated yesterday
    Agent WorkflowsAuto-check passed

More from BuilderIO/agent-native

All 102 skills in this repo

  • Actions

    BuilderIO/agent-native

    How to create and run agent actions. An agent skill from BuilderIO/agent-native.

    7.1k GitHub stars~4.4k tokensUpdated today
    Auto-check passed

  • Client Methods

    BuilderIO/agent-native

    Client method surface rules. An agent skill from BuilderIO/agent-native.

    7.1k GitHub stars~1.2k tokensUpdated today
    Auto-check passed

  • Adding A Feature

    BuilderIO/agent-native

    The four-area checklist every new feature must complete. An agent skill from BuilderIO/agent-native.

    7.1k GitHub stars~4k tokensUpdated today
    Auto-check passed

  • Address Feedback

    BuilderIO/agent-native

    Triage feedback from docs, issues, Slack threads, or pasted notes into verified bugs, UX proposals, unclear questions, and skipped noise.

    7.1k GitHub stars~4.4k tokensUpdated today
    Auto-check passed

  • Audit Log

    BuilderIO/agent-native

    Durable, access-scoped, append-only record of who changed what app data, when, and whether it was the agent or a human.

    7.1k GitHub stars~2k tokensUpdated today
    Auto-check passed

  • Automations

    BuilderIO/agent-native

    Event-triggered and schedule-triggered automations with natural-language conditions.

    7.1k GitHub stars~4.4k tokensUpdated today
    Auto-check passed

Works with

Categories

Questions about A2a Protocol

What does A2a Protocol do?

How agent-native apps discover, authenticate with, and call each other over A2A. A2a Protocol is an agent skill from BuilderIO/agent-native. How agent-native apps discover, authenticate with, and call each other over A2A.

When should I use A2a Protocol?

A2a Protocol fits situations like: connecting one app to another; debugging a remote agent that wont authenticate; exposing skills to peers; calling agents from scripts.

How do I install A2a Protocol in Claude Code?

Run `npx skills add BuilderIO/agent-native --skill a2a-protocol -a claude-code`. Or copy the skill folder (.agents/skills/a2a-protocol in BuilderIO/agent-native) into .claude/skills/a2a-protocol in your project. Claude Code loads it when a task matches its description.

How do I install A2a Protocol in Codex?

Run `npx skills add BuilderIO/agent-native --skill a2a-protocol -a codex`. Or copy the skill folder (.agents/skills/a2a-protocol in BuilderIO/agent-native) into .agents/skills/a2a-protocol in your project. Codex loads it when a task matches its description.

Can I use A2a Protocol in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add BuilderIO/agent-native --skill a2a-protocol -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/a2a-protocol, .gemini/skills/a2a-protocol, .github/skills/a2a-protocol and .opencode/skills/a2a-protocol in your project.

What does A2a Protocol need to run?

Going by SKILL.md and its folder, A2a Protocol needs credentials named A2A_SECRET, ANALYTICS_A2A_TOKEN and ANTHROPIC_API_KEY. Our summary lists: A credential in ANALYTICS_A2A_TOKEN; A credential in A2A_SECRET.

Does A2a Protocol access the network?

SKILL.md names 1 domain. As links in the text: learn.microsoft.com. This is read from the text; nothing was executed.

Is A2a Protocol safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does A2a Protocol use?

No licence was found for A2a Protocol or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.

How many tokens does A2a Protocol use?

About 5.7k tokens (SKILL.md is roughly 23k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to A2a Protocol?

Skills that share tags, products or a category with A2a Protocol: Draw Image (ai-sns/ai-sns, 338 stars), Update A2a Proto (a2aproject/a2a-java, 504 stars), A2a CLI (a2aproject/a2a-cli, 152 stars) and Fix Tck Issue (a2aproject/a2a-java, 504 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains A2a Protocol?

BuilderIO (a GitHub organization) maintains it in BuilderIO/agent-native, which has 7,087 GitHub stars. The repository holds 102 skills in this directory. The repository was last updated on October 8, 2026.

Source: BuilderIO/agent-native on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.