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

Annotations already declare destructiveHint=true, idempotentHint=false and readOnlyHint=false, so the write semantics are covered structurally. The description usefully adds tenancy behavior (a project outside the caller's workspace returns 404), a validation constraint (vision_md must be non-empty), and the return shape — genuine context beyond the annotations. It stops short of saying whether an existing vision is overwritten, which is the key behavioral question for a destructive, non-idempotent setter.

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?

Front-loaded purpose sentence followed by constraints and the return shape; every sentence carries information. Slightly informal and the return-shape line is arguably redundant given the output schema, but there is no padding.

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?

Tenancy, validation, and return values are covered, and the output schema handles the response detail. The remaining gap is meaningful: for a tool annotated destructive and non-idempotent, the description never states whether it replaces an existing vision or how concurrent/duplicate calls behave.

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 must carry the burden and largely does: it defines `vision_md` as free-form markdown that must be non-empty, and describes `project_id` implicitly via the tenant-scoping/404 rule. Both parameters gain meaning not present in the bare string-typed schema.

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 clear resource (the product vision) and the effect of the call ('say what this product is for'), and the informal phrasing is backed by the explicit `vision_md` parameter. It does not, however, distinguish itself from the sibling `set_product_goal` or `get_product_vision`, which an agent must infer from the name alone.

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 clause 'so every run knows what it is building toward' implies the reason to set a vision, but there is no explicit when-to-use guidance, no prerequisite, and no statement of how this differs from `set_product_goal`. Usage is only implied.

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