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 retrieval payload (contact details, appointment count, balance in cents, alert, tags, notes), which is useful, but it discloses nothing about error behavior, missing/invalid ids, or permissions. Adequate, not rich, against an annotation that already covers safety.

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 compact sentence with the essential scope front-loaded, followed by a short GraphQL type mapping. No filler; slightly dense in the field enumeration but nothing 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?

With no output schema, enumerating the returned fields is a genuinely useful addition and largely covers what an agent needs for a one-parameter read tool. It stops short of error/not-found behavior, leaving a minor gap.

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 coverage is 100% and the single parameter's description already supplies the URN format example, so the schema carries the semantics. The description only restates "by id" and adds no format or constraint detail beyond it — baseline 3.

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 one client by id") and enumerates the payload, which cleanly distinguishes it from boulevard_list_clients and boulevard_update_client. An agent can identify the tool without opening the schema.

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?

The phrase "by id" implies a lookup use case, but no alternative is named and there is no stated when/when-not guidance (e.g. use list_clients when the id is unknown). Usage is inferable but not spelled out.

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