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

readOnlyHint=true already declares the safe-read profile, so the bar is lower. The description still adds real value by disclosing the response shape (JSON:API { data }) and that it contains PII, plus the underlying REST endpoint, which signals sensitivity handling. It does not cover auth, rate limits, or not-found behavior.

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 front-loaded sentence plus a compact return/endpoint clause; every element (scope, payload, PII flag, REST mapping) earns its place with no filler.

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 tool with no output schema, the description supplies purpose, return envelope, sensitivity (PII), and the REST analog. Only error/not-found and auth expectations are absent, which is 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 account_id parameter is fully documented with an act_... example in the schema itself. The description adds only 'by id' with no format or validation detail beyond the schema, so the baseline 3 applies.

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 ('Get') and resource ('a single account by id') and clarifies the entity is the persistent identity record for an end user. 'Single' implicitly separates it from the list_accounts sibling, but the sibling is never named explicitly, so differentiation is inferred rather than stated.

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?

Context is implied by 'single account by id' versus the list_* siblings, but there is no explicit when-to-use/when-not guidance, no prerequisite or permission note, and no mention of what to do if the id is unknown. Adequate but leaves routing to inference.

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