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

readOnlyHint=true already declares the safe-read profile, so the description's job is lighter. It adds real value beyond the annotation by disclosing that the response embeds the customer's addresses, which matters because there is no output schema. It stops short of covering pagination/error behavior, but this is a single-item lookup.

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?

Two compact sentences, front-loaded with the verb/resource and then the usage hook. No filler, and the API endpoint note is a single cheap token that aids traceability.

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 with no output schema, the description covers what an agent needs: identity, scope, and the return payload. It could go one step further on the `expand` values, but nothing critical is 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?

Schema description coverage is 100%, so both parameters are documented structurally and the baseline is 3. The description adds the reason the id matters (address ids downstream) but says nothing about the `expand` options beyond what the schema enum already provides.

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 (Fetch) and resource (a single customer by id) with a scope qualifier that separates it from housecall_list_customers. It also names the payload contents (addresses), so an agent knows exactly what it gets back.

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 a concrete downstream reason to call it: the address ids are needed to create a job or estimate, which routes the agent to housecall_create_job/housecall_create_estimate. It does not, however, explicitly say when not to use it (e.g. bulk lookup via list_customers).

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