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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: it discloses the ambiguity and insufficient-evidence return states, that sameAs candidates arrive unapproved, and that Google crosscheck is remotely disabled.

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?

Four dense sentences, each carrying distinct information, with the core purpose front-loaded. There is no filler, though the terse telegraphic style borders on cryptic for terms like 'evidence envelope'.

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 read-only tool with no output schema, the description does cover return states, which is valuable. But it omits any explanation of the required nested envelope structure and refresh semantics, which is a meaningful gap given 0% schema coverage and a nested object parameter.

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 0%, so the description carries the burden. It clarifies max_candidates ('default 3, maximum 5') and implicitly the disabled google_crosscheck flag, but the required 'envelope' object (nested, additionalProperties) and 'refresh' are left entirely unexplained in both schema and description.

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 a verb (discovery) and resource (identity) and specifies scope ('one identity', 'canonical', 'local evidence envelope'). However, 'identity' and 'evidence envelope' are undefined jargon, and it does not distinguish itself from the closely related sibling kg_resolve or kg_audit_identity, leaving the agent to guess which tool to pick.

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?

There is no when-to-use guidance, no prerequisites, and no mention of when this tool should be preferred over kg_resolve, kg_lookup_entities, or kg_audit_identity. The only routing signal is the relational scope of the sibling names, which the description does not leverage.

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