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

Annotations already declare readOnly/openWorld/idempotent, so the safety profile is covered. The description adds substantial behavioral context: it explains the internal cascade across multiple endpoints, that ambiguous matches return `figi_candidates` rather than asserting a single result, that unresolved identifiers are listed explicitly under `unresolved`, and that enrichment degrades gracefully if GLEIF/OpenFIGI is unavailable. This is far beyond the annotation baseline.

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 but packs a lot of necessary detail for a complex multi-entity resolver. It is front-loaded with user-intent examples and a clear purpose, then organized by entity type, followed by degradation behavior and a closing note about internal efficiency. While slightly verbose, every segment earns its place given 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?

With no output schema, the description must convey return semantics, and it does: it lists all returned identifiers, explains labeling by source, describes the `unresolved` section, and covers the ambiguous-match scenario. It also explains how ISIN maps to legal entities. This gives the agent a thorough understanding of what to expect, which is especially important for a tool that replaces multiple manual lookups.

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 100%, but the description adds critical semantics not present in the schema: for the `value` parameter it details acceptable inputs for company (ticker, CIK, name, or ISIN) and drug (brand or generic), and it warns against including trailing security-class words for bond issues. These nuances directly improve the agent's ability to construct valid calls.

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 user queries and then states a precise purpose: 'resolve a user-spoken NAME to the canonical/official identifiers other tools require as input.' It explicitly covers the two supported entity types (company, drug) and lists the specific identifiers returned (CIK, ticker, LEI, FIGI, RxCUI). This clearly distinguishes it from sibling tools like entity_profile or compare_entities, which serve different purposes.

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 an explicit trigger: 'Use FIRST whenever you have a name but need an ID.' It also provides specific usage nuances, such as for bonds: 'pass the ISSUER exactly as printed... never the question's full noun phrase.' This goes beyond a general when-to-use and equips the agent with actionable selection criteria, including how to format input correctly.

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