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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable context beyond that: attribute map values are truncated and should be treated as untrusted user-written input, results include scores and badges plus a dashboardUrl, and missing identities yield null. This helps the agent interpret the return value correctly.

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?

Three sentences carry distinct information: the action and key, the return payload plus trust caveat, and the null behavior. There is no redundancy, and the most important caveat about untrusted truncated data is front-loaded.

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 low-complexity, single-parameter read tool with safety annotations, the description covers invocation, expected output, and the key edge case (identity not found). Although there is no output schema, the description gives enough detail about returned fields for an agent to decide whether to call it and what to do with the result.

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% for the single parameter, which is documented as 'Tracked identity id.' The description mostly repeats that wording rather than adding new semantics. With full schema coverage, the baseline of 3 is appropriate.

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 opens with 'Fetch a single identity by tracked identity id' – a specific verb, resource, and lookup key. It clearly differs from sibling tools like list_identities, get_identity_history, get_identity_analysis, and get_identity_links, so an agent can distinguish it without inspecting schemas.

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 gives clear context: use this when you have a tracked identity id and need a single identity, scoped to the current customer's tenant, with null when absent. It does not explicitly name alternatives or exclusion conditions, but the one-parameter schema and 'single identity' wording make the intended use obvious.

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