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

readOnlyHint=true already tells the agent this is a safe read. The description adds the useful detail that a rich set of related fields is returned, plus the underlying endpoint (GET /jobs/{id}). It does not cover failure behavior (missing job), pagination/expansion cost, or auth requirements, so it adds moderate value over the 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?

A single dense sentence front-loads the action and resource, then lists returns, with the endpoint appended as a compact reference. No filler or redundancy.

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 correctly compensates by enumerating the returned fields, which is the key thing an agent needs. The gap is the unexplained 'expand' option and no error behavior for an invalid id.

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 baseline is 3. The description explains the job_id implicitly ('by id') but says nothing about the 'expand' parameter — what 'attachments' or 'appointments' do, or their cost — even though that is the only non-obvious input.

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 a single job by id') and enumerates what the payload contains — customer, address, status/timestamps, schedule, employees, notes, totals. This clearly distinguishes it from the sibling housecall_list_jobs and from mutation siblings like housecall_update_job_schedule.

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 by 'by id' — call it when you already have a job_id and need the full record rather than a list. There is no explicit when-not guidance, no mention of the alternative (housecall_list_jobs) for discovery, and no note about what to do when the id is unknown.

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