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

Annotations already declare readOnly, idempotent, and non-destructive behavior; the description adds the valuable context that the result is portable, public, and bound to a point in time ('status-as-of limitation'). This is genuine behavioral information beyond the annotation fields, although it does not detail the bundle contents or return shape.

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?

The entire description is one dense sentence that front-loads the action, names the output, states the purpose, and flags the key limitation. There is no filler or repetition of the tool name.

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?

For a one-parameter export with strong safety annotations, the description covers the essential purpose and a key limitation without over-explaining. It could be more complete about what the identity bundle contains or how the status-as-of limitation is surfaced, but an agent has enough context to invoke the tool and interpret its result at a high level.

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 input schema has one required parameter (agent_id) with zero description coverage, and the tool description provides no information about the parameter or how to supply it. The parameter is self-descriptive by name and the schema gives a pattern, but the description itself adds no semantic guidance, so it fails to compensate for the 0% schema coverage.

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 uses a specific verb ('Export') and names a concrete resource ('portable public identity bundle'), with a clear purpose ('offline cryptographic verification') and a distinguishing time limitation. It does not explicitly differentiate itself from siblings such as get_agent_identity_jwks or get_agent_identity_status, but the export-bundle framing is clear enough to identify what the tool does.

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?

It states the intended use case ('offline cryptographic verification') and implicitly warns that the bundle carries a 'status-as-of limitation', which tells an agent not to use it when a live current identity is required. It gives clear context but stops short of naming when-not-to-use or sibling alternatives explicitly.

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