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

Annotations already cover read-only, open-world, idempotent, and non-destructive behavior. The description adds meaningful context: it excludes warrants, CBBCs, ADRs, and other non-HK lines; it states that each match includes the resolved code for disambiguation; and it names the keyless Yahoo Finance source. No contradiction with annotations.

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?

Three tight sentences: the first anchors the purpose, the second adds filtering and disambiguation behavior, and the third gives the source. Every sentence earns its place and the most decision-relevant information is front-loaded.

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 simple two-parameter lookup with no output schema, the description provides enough behavioral context: it explains the returned matches include resolved codes, gives scope boundaries, and notes the keyless source. It does not describe the exact result shape or empty-result behavior, but that is not a critical gap given the schema and annotations.

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?

The input schema already covers both parameters at 100%, including examples, range for limit, and defaults. The description adds minor flavor like English/Chinese company names, but it does not introduce new parameter constraints or semantics that the schema doesn't already provide.

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?

States a specific verb ('Find'), a specific resource ('HKEX stock code for a company by name'), and concrete example queries. It also differentiates from the sibling hk_quote by positioning itself as the lookup step before it and by scoping to Hong Kong-listed equities.

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?

Clearly tells the agent when to use it: as the lookup step before hk_quote, and it gives representative user phrasings. It does not explicitly name alternative resolution tools like resolve_entity or state when to prefer them, but the scope exclusions provide useful selection guidance.

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