Capability registry

What vercel.com declares an agent can do

Measured 2026-10-04 06:00 UTC from the declarations the site publishes (record mszfnjif4r). Each capability is shown as declared, under the policy class that decides whether anything may call it, beside what a call observed.

10declared

0public read-only

0called and verified

0declared ≠ observed

agent_skill, apiprotocols

Metadata 10

Declared versus observed

Capability	Policy class	Declared	Observed
https://api.vercel.com api · https://api.vercel.com	Metadata never called automatically	an API the catalog lists; its operations are in its own description auth: unknown	not attempted on another origin (api.vercel.com): only the scanned origin is called
deploy-to-vercel agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/deploy-to-vercel.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-cli-with-tokens agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-cli-with-tokens.md	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-composition-patterns agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-composition-patterns.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-optimize agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-optimize.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-react-best-practices agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-react-best-practices.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-react-native-skills agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-react-native-skills.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
vercel-react-view-transitions agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/vercel-react-view-transitions.tar.gz	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
web-design-guidelines agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/web-design-guidelines.md	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called
writing-guidelines agent_skill · https://github.com/vercel-labs/agent-skills/releases/download/agent-skills-063bee94c3f4df8453406c830b0a7df0f2860278/writing-guidelines.md	Metadata never called automatically	an instruction file an agent reads; not an operation auth: none	not attempted on another origin (github.com): only the scanned origin is called

Where the declaration and the call disagree

None: every capability that was called answered as declared.

Signed certificate

This page’s rows, signed by the observer’s Ed25519 key: every capability’s id, endpoint, safety class, policy class and observed state, the declaration hashes and the record’s sealed manifest. The certificate is derived from the record alone, so the same record always yields the same id.

certificate_id ccap1:22c15de163e2f9fc9eb2f4fa15fc023c401312e5fe7306633b3c90fa24fc4aa6
alg Ed25519 · kid hcIAczGf-8EFBnkunmZlvFWnD2nHHeHeC9cM4BTiBVo
sig hTaK0gaIigr1FaAo324fdOdmbc47ooj5_M_S9wtCH_421P1hDM9Nqy3zuwjvSlcUEfVt_f0G7mPzs5HYO22BAA

The certificate as JSON · verify it now · the key directory · machine-readability certificate

To verify it yourself: SHA-256 the certificate object as canonical JSON (keys sorted, no whitespace); the hex digest must equal certificate_sha256 and the id; then check the Ed25519 signature over "crawlcheck-capability-certificate-v1\n" followed by that hex digest, with the key in the directory whose RFC 7638 thumbprint is the kid.

Policy classes

Policy class	Called automatically?	Rule
Public read-only public_read_only	yes, to verify	May be called without credentials. CrawlCheck calls it only to check the declaration: GET with no input, on the scanned origin.
Authenticated read-only authenticated_read_only	never	Never called by CrawlCheck. An agent needs the user's own credentials and consent.
Reversible write reversible_write	never	Never invoked automatically. Needs the owner's written authorisation and a test account.
Irreversible write irreversible_write	never	Never invoked automatically. Deletes or changes something that cannot be undone.
Financial financial	never	Never invoked automatically. Moves money or creates a charge.
External communication external_communication	never	Never invoked automatically. Sends a message, email or notification to someone.
Identity and accounts identity	never	Never invoked automatically. Creates, signs in to or changes an account or credential.
Unknown unknown	never	Never invoked. Its effect cannot be read from the declaration, so it is treated as the riskiest case.
Metadata metadata	never	Nothing to invoke: a listing, a server card or a skill file, not an operation.