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

The description discloses internal cascading lookups, graceful degradation if GLEIF or OpenFIGI is unavailable, the fact that multiple lookup endpoints are hit, and the behavior of returning EDGAR identifiers even when enrichment fails. It also clarifies that non-equity instruments resolve even though they have no ticker, and explains what happens with ISIN mappings. Combined with annotations declaring readOnly, openWorld, idempotent, and non-destructive hints, the agent has a well-rounded behavioral picture.

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 long and quite detailed, but every portion adds operational value: query examples, supported types, behavior for non-equity instruments, ISIN behavior, degradation behavior, and cascading lookup count. It front-loads the most distinguishing information (query patterns and 'use first' rule) before diving into enrichment detail. A 4 rather than 5 because the parameter guidance could be more tightly organized, and the description is verbose enough that an agent must parse a substantial block of text.

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?

Given the tool's complexity—two entity types, multiple external sources, varying identifier formats, degradation behavior, and no output schema—the description is thorough and covers the important edge cases (non-US issuers, non-equity instruments, drug citations, and fallback behavior). It answers likely agent questions about when to use it and what inputs are valid. There is no output schema, but the description explicitly discloses the return values (CIK, ticker, company_name, LEI, FIGI, RxCUI, ingredient, brand), which substitutes for the missing structured output documentation.

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 coverage is already 100%, so the baseline is 3. The description adds extra semantic value by disambiguating the 'value' parameter with a direct example for bonds (pass the issuer exactly as printed, not the full noun phrase) and explaining that trailing security-class words will cause the FIGI lookup to fail. It also clarifies how ISINs map to legal entities through GLEIF, which the schema alone does not convey. Not a 5 because the description is somewhat dense and the parameter guidance is embedded inside a long narrative rather than structured as explicit parameter notes.

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 concrete query examples and states the core function: resolving user-spoken names to canonical identifiers that other tools require. It explicitly distinguishes itself from siblings by naming the two supported types (company, drug) and the identifier domains covered (CIK, ticker, LEI, FIGI, RxCUIs), which makes the tool's purpose impossible to mistake.

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 an explicit usage rule: "Use FIRST whenever you have a name but need an ID." It also gives detailed routing guidance for non-equity instruments, ISINs, drugs, and when enrichment degrades. This goes well beyond a vague 'use when you need an identifier' and tells the agent exactly when to invoke resolve_entity versus alternatives.

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