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

The description adds substantial behavioral context beyond the annotations: it discloses cascading internal lookups, graceful degradation when GLEIF or OpenFIGI is unavailable, explicit handling of unresolved identifiers via an `unresolved` field, behavior when a name maps to multiple instruments (`figi_candidates`), and source labeling for each identifier. This is far beyond the readOnly/openWorld/idempotent hints already present.

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 front-loaded with the use case and 'Use FIRST' guidance, which is ideal. It is long and dense, but most sentences earn their place given the tool's complexity and the lack of an output schema. A few parenthetical asides add length without much new information, so it is not maximally concise.

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 two-parameter tool with no output schema, the description is remarkably complete. It covers supported types, accepted input formats, edge cases (ambiguous matches, non-equity securities, unavailable external sources), and expected behavior around unresolved identifiers. An agent has enough context to know when this tool applies and what it will return in tricky situations.

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 schema already covers both parameters thoroughly, so the baseline is 3. The description adds meaningful extra semantics: it introduces ISIN as an accepted input not listed in the schema, explains the distinction between exact ticker mapping and name search, and provides a concrete negative example ('NEW YORK ST DORM AUTH revenue bonds') to clarify what should not be passed in `value`. This exceeds what the schema alone provides.

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 clear, specific purpose: resolving a user-spoken name or identifier into canonical/official identifiers required by other tools. It lists concrete example queries, supported entity types (company, drug), and distinguishes itself from sibling tools like entity_profile by framing it as the first step when an ID is needed.

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 explicitly says to use this tool 'FIRST whenever you have a name but need an ID,' which is strong usage guidance. It also enumerates accepted input forms (ticker, CIK, ISIN, company name, brand/generic drug name) and supported entity types. However, it does not explicitly mention when not to use it or name specific alternatives, so it falls just short of a 5.

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