Agent Card specification: inspect fields and client compatibility

Version and limits

This is a direct document inspector, so results remain inspectable without an animation. It implements only the checks listed in the guide, based on A2A 0.3.0 specification, sections 5.5 and 5.6. It is not a full schema validator or live service test. All endpoints are fictional; credentials are boolean availability flags. The size is the actual UTF-8 encoding of the editor text.

Inspect a card before selecting an endpoint

An Agent Card describes a service; it is not proof that the service exists or that its claims are true. This direct inspection tool parses editable JSON and evaluates a deliberately bounded A2A 0.3.0 field profile. It computes the UTF-8 byte length of your actual text, reports each checked field, and evaluates a fictional client against the advertised interfaces, skill modes, streaming flag and security alternatives. The agent version 1.2.0 is independent of protocolVersion 0.3.0. This historical version uses url, preferredTransport and additionalInterfaces; it is not the newer supportedInterfaces format. The related field-reference article describes 1.0; use it to compare the versions, not as the schema for this historical fixture.

Make a concrete field failure

Start with Valid card. Remove the name property from Card JSON and the field report rejects it; restore the property and the report accepts the checked fields. Missing name creates this same case for you. Malformed JSON fails before field checks. Restore defaults resets both the card and every client option. Load selected fixture discards JSON edits while keeping client choices. Editing any JSON character or changing a client choice recomputes the result immediately. There is no timer, network request, hidden task execution or simulated throughput.

Follow transport and mode selection

Client transport chooses JSONRPC, HTTP+JSON or GRPC. The default card selects its main JSONRPC endpoint; HTTP+JSON selects the additional REST endpoint, while GRPC has no match. Require HTTPS is a client policy. Insecure endpoint changes the main URL to HTTP; disabling this policy permits that fictional endpoint without claiming it is safe. Requested skill selects summarize, echo or a missing identifier. Input and Output MIME types compare exact strings. Summarize overrides the default output with application/json, whereas echo inherits text/plain. Select Output text/plain with summarize to expose the override failure. This example does not negotiate MIME wildcards or parameters.

Separate capability and credential checks

Require streaming blocks a card whose streaming flag is false or absent. No streaming creates that case; turn off the requirement to permit a nonstreaming interaction. Bearer credential available and API key available are symbolic availability switches, not actual tokens. The default security array offers bearer OR key: either switch suffices. Both credentials required places both scheme names inside one requirement object, so both must be present. Separate objects are alternatives; names in the same object are combined. Turning off both switches blocks both presets. Neither switch authenticates a real request or grants authorization. Never paste real credentials into the editor.

Distinguish a bounded check from conformance

The field report checks identity strings, HTTP(S) endpoint shape, transport strings, three capability booleans, skill identity and mode arrays, plus HTTP and API-key declarations and references. Duplicate skill IDs are rejected as a client policy. Unsupported security types and nonempty scope arrays are rejected by this profile, not declared invalid in the whole protocol. Provider metadata, extensions, skill-level security, signatures and other optional fields are outside its conformance coverage. Client compatible means only the displayed gates passed. There is no signature verification, DNS lookup, credential verification, authorization, schema certification, cache, retry or capacity benchmark.

Keep a reproducible comparison

The parsed decision exposes the selected endpoint, inherited or overridden mode lists, and each security alternative. Export inspection downloads exactly this result as JSON. Capture baseline saves the current summary; Replace baseline updates it and Clear baseline removes it. Write your chosen preset and client changes in the notebook, then Export notes to retain observations. Expand experiment and Exit full screen change the viewing area only. Compare valid JSON, missing identity, an unsupported transport and the two security arrangements before drawing conclusions. The byte count includes indentation and non-ASCII text, so it measures serialization size rather than task capacity or network latency.