Who Am I

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, not open-world), and the description adds genuinely useful context beyond them: the contents returned and the source of truth (its .fafa card), which aligns with openWorldHint=false. It is silent on failure behavior when no card exists, so it stops short of full disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with the identity statement first and the field/source detail immediately after. Every clause earns its place with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no parameters and no output schema, the description usefully compensates by listing the fields that come back. It is nearly complete; only edge behavior (missing/invalid .fafa card) is unaddressed, which is a small gap for an identity probe.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so the schema baseline of 4 applies. Nothing in the description is needed to explain inputs, and none is misdescribed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the specific resource (the server's OWN identity, not the caller's) and enumerates the returned fields (name, vendor, version, status, license). This disambiguates it well against siblings like list_context_sources or read_agents_md, though it never names an alternative directly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent infers it should call this when it needs to know what server it is talking to. There is no explicit when-to-use, when-not-to-use, or named alternative among the sibling tools, but for a trivial zero-argument probe the omission is minor.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.