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

Annotations already disclose read-only, idempotent, non-destructive behavior. The description adds only the selection semantics ('canonical', 'stable identifier') and no extra operational detail such as error behavior or canonicalization implications.

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 sentence, front-loaded with the verb and resource, with no filler. Every word ('one', 'canonical', 'stable identifier') carries meaning.

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 one-parameter read with rich annotations, the description is nearly adequate, but it never explains what a SHAR service is or what the returned service entity contains. With no output schema, a bit more return context would make it self-sufficient.

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 sole parameter serviceId has no schema description, so the description must carry the semantic weight; 'stable identifier' tells the agent the ID is stable and canonical but not its format, source, or how to discover it. This is partial compensation for a simple one-parameter tool.

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?

The description uses a specific verb ('Retrieve') and resource ('canonical service'), and specifies lookup by stable identifier, so the tool's action is clear. It doesn't explicitly differentiate from siblings like list_services or get_case, but the singular canonical service + stable identifier wording implies direct ID fetch.

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 stable identifier' sets a clear prerequisite: use this when you already have a stable service ID. It gives no explicit guidance on when not to use it or which sibling to prefer for browsing/searching.

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