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

Annotations already provide readOnly/idempotent/non-destructive hints, but the description adds substantial non-obvious behavior: unresolved identifiers are returned under `unresolved` rather than omitted, ambiguous name matches return `figi_candidates`, LEI/FIGI enrichment degrades gracefully, and internal cascading replaces multiple lookups. No contradiction 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 and heavily parenthetical, which hurts scanability, but every major clause adds useful operational information. It is front-loaded with example utterances and the 'Use FIRST' rule, making the primary purpose immediately clear before the deep detail.

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 and two complex entity types, the description covers input constraints, output components (CIK, ticker, LEI, FIGI, RxCUI, source labels), special cases (non-equity instruments, non-US issuers, ambiguous matches), and failure behavior (graceful degradation). It is sufficiently complete for an agent to invoke the tool 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?

Although schema coverage is 100%, the description goes far beyond the schema. It details accepted formats for company (ticker, CIK, ISIN, name), drug brand/generic names, and gives a critical usage warning: pass the entity name only, not the full noun phrase (e.g., 'NEW YORK ST DORM AUTH' not 'revenue bonds'). This materially improves correct invocation.

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 uses a specific verb ('resolve') and resource ('user-spoken NAME to canonical/official identifiers'), reinforced by concrete example queries. It clearly distinguishes itself from sibling tools by stating it supplies the IDs other tools require as input and positions it as the first tool to use when a name needs an identifier.

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?

Gives explicit guidance: 'Use FIRST whenever you have a name but need an ID', plus clear context about accepted input formats and ambiguity behavior. It does not explicitly name alternative sibling tools or state when not to use the tool, but the use condition is strong and actionable.

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