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

Annotations already declare readOnlyHint=true, and the description adds genuinely new behavior: the call is free, and the quote reflects the project's current state ("as it is now"), implying it must be re-run after edits. The return shape including fits/blockers reveals that pricing can fail validation, which is useful context beyond the annotation.

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?

The critical fact ("Free") is front-loaded and the workflow hint follows immediately. The Args line "project_id: project" is essentially wasted text, a minor inefficiency in an otherwise tight definition.

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-parameter read-only tool with no output schema, the description supplies the return object shape (quote with render_cents, fits, blockers, items) and the downstream handoff to studio_render, which is what an agent needs to act on the result. Only the semantics of blockers/fits are left unstated.

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 schema already documents project_id with its sp_ pattern and origin from studio_list_projects. The description's "project_id: project" restates the parameter without adding format, sourcing, or constraints, so it neither helps nor harms beyond the baseline.

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 server's render price for the project as it is now" states a specific verb (price) and resource (project), making clear this is a non-mutating cost check rather than an actual render. It is distinguishable from studio_render by the follow-up instruction to pass render_cents as confirm_cents, though the sibling is referenced only by workflow, not by explicit contrast.

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?

"Free" tells the agent this is cheap to call, and "Pass render_cents to studio_render as confirm_cents" explicitly places it in the workflow before rendering. There is no explicit when-not guidance (e.g. what to do if blockers are non-empty), but the intended usage context is clear.

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