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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds useful context beyond that: it returns JSON:API data and relationships and maps to GET /api/customers/{id}. It does not cover not-found behavior or error semantics, but for a simple read tool the added disclosure is meaningful.

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?

Three short sentences, front-loaded with the core action and scope. The return behavior and endpoint are tacked on without redundancy or wasted words.

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-record read with one required parameter, readOnly annotations, and no output schema, the description gives enough to call it correctly. It mentions the returned JSON:API shape and endpoint; the main missing piece is error/not-found handling, which is minor here.

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 0%, so the description needs to carry parameter meaning. It identifies the id as a numeric record id, which is somewhat helpful, but the schema pattern already enforces digits and the description does not explain where the id comes from or how it relates to customer identity.

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 states a specific verb and resource ('Read one TOConline customer') and clarifies retrieval by numeric record id. It implicitly separates itself from the list endpoint by saying 'one', but it does not name toconline_list_customers or other siblings explicitly.

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: use this when you already have a customer record id and need a single customer. There is no explicit guidance on when to choose this over toconline_list_customers, nor any stated prerequisites or exclusions.

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