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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, but the description adds substantial behavioral context beyond them: it cascades through multiple lookup endpoints, degrades gracefully when external sources are down, labels identifier provenance, explicitly reports unresolved identifiers, and returns figi_candidates rather than asserting a single match. This deeply informs the agent about the tool's behavior.

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 exceptionally dense and contains valuable, non-obvious details, but it is largely one sprawling paragraph with heavy parentheticals and embedded clauses. It would be more concise and scannable with bulleted type-specific breakdowns; the detail is useful, but the structure makes it harder for an agent to quickly extract the core contract.

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 carries the burden of explaining return behavior, and it does so well: it names returned identifiers (CIK, ticker, LEI, FIGI, RxCUI), states how sources are labelled, describes the unresolved field, and explains the figi_candidates response for ambiguity. For a two-parameter tool with complex multi-source behavior, nothing essential is missing.

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 coverage is 100%, but the description significantly extends meaning: it explains that value can also be an ISIN for company lookups, warns against passing full noun phrases for bonds, clarifies that trailing security-class words break the FIGI match, and distinguishes accepted inputs per type. This goes well beyond the schema's minimal 'ticker, CIK, or name' definition.

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 names the exact action — resolving a user-spoken NAME to canonical identifiers — and enumerates the concrete question forms that trigger it, plus supported types (company, drug). It clearly differentiates this tool from siblings by positioning it as the required input provider for other tools, and explains edge cases like non-equity instruments and ambiguous matches.

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 strong when-to-use guidance. It explains ambiguity handling and notes fallback behavior when LEI/FIGI enrichment is unavailable. However, it does not name alternative sibling tools (e.g., entity_profile) to explicitly state when not to use this tool.

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