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

readOnlyHint=true already tells the agent this is a safe read, and the description adds only the raw endpoint path (POST /v1/plans.get) – a transport detail with little decision value. It says nothing about behavior on a missing plan id, error shape, or that the POST is a semantic read despite the verb.

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?

Two compact sentences, front-loaded with the purpose. The trailing API endpoint note is low-value filler for an agent but does not bloat or bury the main statement.

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 trivial two-parameter read with full schema coverage and a readOnly annotation, this is nearly sufficient, but with no output schema the description never hints at what a plan object contains or what happens when the id is unknown.

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%, including the 'defaults to the latest' semantics for version, so the description's 'optionally a specific version' merely restates the schema. Baseline 3 applies since the schema does all the parameter work.

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 plan by id') and the parenthetical version qualifier makes clear it is a point lookup rather than a listing. This implicitly separates it from autumn_list_plans, though that sibling is never named.

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 only implied: 'single plan by id' hints at when this is preferred over a list call, but there is no explicit when-to-use, no prerequisites (e.g., plan must exist), and no named alternative for browsing plans.

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