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

Annotations already indicate read-only, idempotent, non-destructive. The description goes far beyond: it discloses the cascading internal lookup behavior, graceful degradation if GLEIF/OpenFIGI is unavailable, ambiguity handling (returns figi_candidates, asserts nothing), source labeling, and the unresolved field. It also explains the input format caveat for bonds. This is rich behavioral context that annotations alone cannot convey — no contradiction.

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 and dense, but well-structured with clear paragraphs and lists (supported types, behavior notes). The most critical usage guidance ('Use FIRST whenever...') is front-loaded, and every sentence adds value by explaining a scenario, caveat, or behavior. Slightly verbose but not wasteful; earns its length.

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?

Despite no output schema, the description explains what is returned (identifiers, unresolved items, figi_candidates) and the behavior around each. It covers edge cases (ambiguity, unavailable sources, non-equity instruments) and input requirements thoroughly. For a tool with this complexity (cascading lookups, multiple sources), the description is complete and leaves no critical gap.

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 substantial meaning: it explains acceptable formats for 'value' (ticker, CIK, name for company; brand/generic for drug), illustrates with examples, and provides a critical warning about not including security-class words for bonds. It also clarifies the 'type' enum semantics. This goes beyond the schema's basic type descriptions.

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 clearly states the verb ('resolve') and resource ('user-spoken NAME to canonical/official identifiers'), and explicitly differentiates from siblings by explaining that it produces identifiers other tools require as input. It covers supported types (company, drug) and describes the cross-source identity spine, making 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 gives explicit when-to-use guidance: 'Use FIRST whenever you have a name but need an ID.' It also explains specific scenarios (bonds, drug names) and provides a critical input caveat (pass entity name only). However, it does not explicitly state when not to use the tool or name alternative tools, though the phrase 'replaces 2-3 manual lookups' implies the alternative is manual lookup. Slightly lacking in exclusions but strong on positive usage.

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