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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description adds valuable privacy context (no birth data stored or logged, including request bodies, queries, access logs, stats and errors) which is not captured by annotations. It doesn't explain output structure, but an output schema exists to carry that.

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, front-loaded with the core purpose, then disambiguation rule, then privacy note. Efficient overall, though the privacy clause is long and slightly dense for a single sentence.

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?

An output schema exists, so return values needn't be detailed. The description covers purpose, disambiguation behavior, and privacy guarantees; it's complete enough for an agent to invoke correctly, though it could say more about what happens on no-match or the lang fallback note.

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 50%: lang is documented in the schema (with fallback behavior), but query has no description. The description doesn't add syntax or format details for query beyond the example phrases, so baseline 3 applies—the schema does most of the work.

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 states a specific verb (Find) and resource (disambiguated birthplace candidates and GeoNames ids), plus example queries in multiple languages. It's clearly distinguishable from sibling tools like get_big_three or calculate_birth_chart, which deal with chart/astrological data rather than place lookup.

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?

Explicit when-to-use guidance: 'Ask the user to choose when more than one plausible match exists; never guess.' This directly tells the agent how to behave on ambiguous results, which is the key decision point for this tool.

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