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

Annotations already mark this read-only, idempotent, and non-destructive, so the description adds significant behavioral value beyond them: it discloses fan-out across multiple LiveDataLink sources, per-source confidence, the non-fatal handling of source failures, omitted source classes (UEI/SAM.gov, RDAP), and the caveat to verify identifiers before relying on a join.

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 but front-loaded with its core role and value proposition. Every major element—sources, outputs, failure behavior, exclusions, verification caveat—earns its place. It is longer than minimal, but the length is justified by the tool's breadth; only minor phrasing like 'Premium cross-source synthesis' adds limited signal.

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 full burden of explaining return values, and it does so thoroughly: compact canonical-IDs block, per-source confidence, entity-type guess, ownership summary, sanctions flag, and overall confidence. It also covers edge behavior ('A source that fails is noted, not fatal'), source exclusions, and verification guidance, making it complete for a high-complexity tool.

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%, and the input schema already explains each parameter's role—CIK hints, EIN for exact nonprofit match, state for disambiguation, ticker to pin SEC EDGAR. The description restates these hints at a high level but adds no meaningful semantic details beyond the schema, so the baseline 3 applies.

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 begins with a specific role—'Canonical cross-source entity resolution' and 'join-key primitive'—and enumerates exactly what the tool returns: canonical identity, source-specific IDs, confidence, entity-type guess, ownership summary, and sanctions flag. It explicitly distinguishes itself from entity_dossier's full narrative, so the agent can differentiate this tool without opening schemas.

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 strong contextual guidance: 'run before other combos' signals when to use it as a key-resolution step, and 'distinct from entity_dossier's full narrative' points to an alternative. However, it does not explicitly name near-sibling tools like entity_resolve or state when NOT to use this tool, leaving some routing to inference.

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