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

Even with readOnlyHint, openWorldHint, idempotentHint, and destructiveHint all provided, the description adds substantial behavioral detail: it cascades through several lookup endpoints, exposes figi_candidates when a name is ambiguous, explicitly reports unresolved identifiers instead of omitting them, and degrades gracefully when GLEIF or OpenFIGI are unavailable. It also explains the EDGAR limitation and how ISINs resolve through GLEIF, going well beyond the annotations.

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 very long and dense, but it is front-loaded with examples and the key 'Use FIRST' directive, and every block adds operational value (supported types, ambiguity behavior, degradation, input restrictions). It is not concise in length, but it is well-structured and avoids repetition; the verbosity is justified by the tool's complexity.

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 tool with no output schema but high complexity, the description is remarkably complete: it covers supported entity types, input quirks, identifier sources, ambiguity handling, unresolved-identifier behavior, and failure mode degradation. It does not specify an exact JSON response shape, but it describes the key outputs (canonical IDs, candidates, unresolved list), which is sufficient for an agent to invoke and interpret 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?

Although the schema already covers 100% of parameters, the description enriches the 'value' parameter with critical semantics: pass the entity name only, not the full noun phrase, with a concrete bond example ('NEW YORK ST DORM AUTH' not 'NEW YORK ST DORM AUTH revenue bonds'). It also clarifies accepted inputs per type (ticker, CIK, ISIN, brand/generic name), adding meaning the schema alone lacks.

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 natural-language queries ('What's the ticker for…' / 'find the CIK for…'), then states the precise purpose: resolve a user-spoken name to canonical/official identifiers that other tools require as input. It differentiates itself from siblings by positioning it as the 'FIRST' step when a name but not an ID is available, and by naming the specific identifier types it returns (CIK, LEI, FIGI, RxCUI).

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 explicit usage guidance: 'Use FIRST whenever you have a name but need an ID,' and explains that it replaces 2-3 manual lookups. It also clarifies entity-type dispatch (company vs drug) and supported input forms. It does not explicitly name sibling alternatives or state when not to use it, but the 'first step' framing is strong context.

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