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

Beyond the readOnly/idempotent/openWorld annotations, the description discloses important runtime behaviors: multi-match instruments produce figi_candidates rather than a forced assertion, unresolved identifiers are explicitly listed under unresolved, LEI/FIGI enrichment degrades gracefully if upstream sources fail, and each call cascades through several internal lookup endpoints. This is substantial, decision-relevant behavioral detail.

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 the tool genuinely contains many edge cases (multi-match, non-equity instruments, ISIN mapping, degraded enrichment, unresolved tracking), so the length is largely justified. It is organized by entity type with the primary rule 'Use FIRST' front-loaded; it earns most of its sentences, though trimming redundant example phrasings could make it tighter.

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 present, the description carries the full burden of explaining what the tool returns, and it does so thoroughly: identifier types, source labels, unresolved fields, figi_candidates, ownership data, and graceful degradation. For its complexity, nothing essential appears 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?

Although the schema covers all parameters, the description adds crucial semantic guidance: pass the ENTITY NAME ONLY, for bonds use the issuer exactly as printed, and never append security-class words like 'revenue bonds' because the FIGI lookup matches instrument names. It also clarifies that ISIN input resolves to the issuing legal entity via GLEIF, which materially helps an agent construct correct 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 uses a specific verb-resource pair — 'resolve a user-spoken NAME to the canonical/official identifiers other tools require as input' — and distinguishes the tool as the name-to-ID step upstream of siblings like entity_profile or compare_entities. It enumerates supported types (company, drug) and the concrete identifiers returned (CIK, ticker, LEI, FIGI, RxCUI), leaving no doubt about what it does.

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?

It gives an explicit directive: 'Use FIRST whenever you have a name but need an ID.' This clearly states when the tool is appropriate and positions it as a prerequisite for other tools. It stops short of naming alternative tools or stating when NOT to use it, so it does not fully meet the 5-level bar.

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