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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds context beyond them: the result is text rather than structured data, it enumerates what the record contains (price, rooms, description, agent, last-verified timestamp, viewing link), and it warns that viewings and enquiries go to the agent rather than Homedex.

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?

One dense, front-loaded sentence sequence: resource and key first, then payload contents, then the sibling relationship. The id example is repeated from the schema, which is mild redundancy, but no sentence is otherwise wasted.

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 single-parameter read tool with an output schema and full annotations, the description covers the call site, the source of the id, the nature of the response (text) and the sibling alternative. Nothing material is missing for an agent to select and call it correctly.

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 single id parameter's meaning and example format are already documented in the schema. The description restates the provenance of the id from search but adds no syntax or validation detail beyond that, 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?

States a specific verb and resource — fetch the full details of one home — and pins the key as the id returned by search, with the Homedex number format shown. It also distinguishes itself from siblings: search produces the id, and get_listing returns the same record as structured data.

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?

Gives clear context (use it after search, with the id search returned) and names the alternative, get_listing, for callers that want structured data, plus the intended consumer (standard search-and-fetch clients like ChatGPT deep research). It stops short of an explicit 'do not use when' instruction or guidance on an invalid/unknown id.

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