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

Annotations already declare readOnly, idempotent, non-destructive and closed-world behaviour, so the bar is lower; the description still adds substantial value by disclosing provenance (source page and read date), per-market 'not_on_record' semantics, a no-inference policy, a typed error taxonomy, and routing via the owning node door. The remaining gap is that it does not say what the response looks like structurally.

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 core purpose is front-loaded, but the text is a dense run-on with jargon such as 'receipted', 'signed by the node', and 'Door:' that costs clarity. The final sentence about doors and routing is operationally interesting but competes with the primary call information.

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 two-parameter, read-only lookup with no output schema, the description covers return content, per-market gaps, error types and provenance, which is nearly everything an agent needs to call it correctly. Only the shape of the returned payload is left implicit.

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%, so the schema already documents both parameters including the exchange-qualified ticker format. The description restates ticker/ISIN/LEI and refers to markets but adds no syntax or constraints beyond what the schema provides; 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 states a specific verb and resource: given an issuer (ticker, ISIN or LEI) it returns the auditor of record plus every dated auditor change. It is clear what the tool does, but it never names or contrasts the sibling tools (resolve_issuer, list_nodes), so differentiation relies on the name alone.

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?

Usage is implied rather than stated: you call it when you need an issuer's auditor, and the mention of 'ambiguous' and 'unknown_issuer' hints that disambiguation may be needed first. However, there is no explicit guidance to use resolve_issuer before this tool, and no stated when-not-to-use condition.

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