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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds significant behavioral nuance beyond annotations: it cascades through multiple lookup endpoints internally, LEI/FIGI enrichment degrades gracefully, and unresolved identifiers are stated under 'unresolved' rather than omitted. It also clarifies that an ISIN resolves to the legal entity via a GLEIF ISIN-to-LEI mapping, which is non-obvious behavior an agent would otherwise not know.

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 information-dense: every clause adds a distinct fact, from input formats to degradation behavior to the internal cascade. The opening example list front-loads the purpose, and the supported types are clearly organized. The only deduction is that the parenthetical about non-equity instruments is somewhat sprawling and could be tightened without losing meaning.

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, the description compensates thoroughly: it states what identifiers each type returns, what unresolved values look like, how enrichment degrades, and what input forms are accepted. The description covers the agent's decision needs for calling this tool and interpreting the result, with no obvious missing piece.

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%, so both parameters are already explained in the schema. The description adds meaning by enumerating accepted input forms for company (ticker, CIK, name) and drug (brand or generic), and by giving the crucial negative instruction for bond issuer names: pass the issuer exactly as printed, not the full noun phrase. It also clarifies that an ISIN-like input is accepted for company type, which the schema doesn't state. This is meaningful value beyond the schema, though the schema already carries most of the semantic weight.

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-phrase examples and a precise mission: resolve a user-spoken NAME to the canonical/official identifiers other tools require. It names specific identifier types (CIK, ticker, LEI, FIGI, RxCUI) and supported entity kinds (company, drug), and it distinguishes itself from sibling tools like entity_profile and compare_entities by positioning resolve_entity as the ID-lookup step. The verb 'resolve' plus the explicit output objects make the purpose unmistakable.

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,' which is a clear when-to-use directive. It also explains what to pass for each supported type and warns against passing the full noun phrase for bond issuers, with a concrete negative example. It further explains when non-equity instruments resolve here and how enrichment degrades, which guides an agent to expect success/failure modes.

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