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

Annotations already declare read-only, open-world, idempotent, and non-destructive hints. The description adds substantial behavioral context beyond those: graceful degradation when GLEIF/OpenFIGI is unavailable, ambiguity resolution via figi_candidates, explicit labeling of identifier sources, the unresolved field, and internal cascading through multiple lookup endpoints. No contradictions with 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 dense with valuable information, and it front-loads user phrasing examples and the core purpose. However, it is long and somewhat stream-of-consciousness, relying on nested parenthetical clauses. The length is largely justified by tool complexity, but restructuring into bullet points would aid scanning.

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?

This is a complex tool with no output schema, yet the description compensates thoroughly. It explains return contents (CIK, LEI, FIGI, figi_candidates, unresolved), edge cases (non-equity instruments, non-US issuers via ISIN-to-LEI), and failure behavior (EDGAR still returns if GLEIF/OpenFIGI is down). An agent has everything needed to use it correctly.

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?

Even though schema description coverage is 100%, the description adds significant meaning over the schema. It clarifies acceptable inputs for value: ticker, CIK, ISIN, or name for companies; brand or generic name for drugs. It also gives critical formatting guidance, such as passing only the issuer name rather than trailing security-class words, with a concrete example.

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 the verb 'resolve' and the exact resource: user-spoken names to canonical/official identifiers. It opens with concrete example queries and explicitly distinguishes itself by producing identifiers 'other tools require as input', which clearly separates it from siblings like entity_profile and reverse.

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 'Use FIRST whenever you have a name but need an ID', giving a direct trigger condition. It also mentions that it replaces '2-3 manual lookups', implying it is the preferred entry point. However, it does not name specific alternative tools or state when not to use it, so exclusion guidance is missing.

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