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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, fully covering the safety profile. The description adds no extra behavioral context (e.g., error behavior, return structure, or side effects) but is consistent with the annotations, so a 3 is appropriate given the lowered bar.

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 description is a single, direct sentence that front-loads the action and resource. It contains no filler or redundant detail, earning its place perfectly for a simple getter.

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 read tool with output schema and safety annotations present, the description is complete enough. It could optionally mention the return type or require an existing id, but the output schema and schema description already cover those details, leaving only minor gaps.

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?

Schema description coverage is 100%, and the id parameter's description already explains that it is Underlayer's id, not externalId, and where to obtain it. The tool description merely restates that the tool fetches by id, adding no meaningful semantic value beyond the schema, so the baseline 3 applies.

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 'Fetches one identity by id' uses a specific verb and resource, clearly distinguishing this singular getter from siblings like list_identities (plural), upsert_identity, and delete_identity. The title 'Get identity' reinforces the purpose, leaving no ambiguity about 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?

The description provides no guidance on when to use this tool versus alternatives such as list_identities or get_workspace_info. There are no stated selection criteria, exclusions, or prerequisites, leaving the agent to infer usage from the name and parameters alone.

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