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

Annotations already establish readOnly/idempotent/non-destructive, and the description reinforces this with 'Spends nothing', which is exactly the behavior an agent needs to trust a dry run. It goes further with real behavioral detail absent from annotations: the gate is authoritative, refusals name the exact price, and 'refused'/'planned' semantics for render_score. It does not describe the returned estimate structure (cost fields, whether a breakdown is included), leaving some behavioral surface undisclosed.

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-loading is strong: the purpose and zero-cost guarantee come first. However, the description re-enumerates all 24 enum values already fully specified in the schema, which is pure duplication, and packs job-specific arg rules into one run-on parenthetical spanning multiple sub-cases. Roughly a third of the text could be cut without information loss.

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 two-parameter, no-output-schema pricing tool, this covers intent, safety, arg relevance, and refusal behavior — enough to invoke correctly and interpret a refusal. Remaining gaps are modest: the actual shape of a successful estimate (what fields a cost estimate returns) is never characterized beyond 'the planes' own price table', and there is no indication of latency or rate limits for repeated quoting.

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%, so baseline would be 3, but `args` is a free-form object with additionalProperties, and the description meaningfully constrains it by naming the price-relevant keys (duration_seconds, models, instruments, notes/bpm, voice_split) and giving pricing rules the schema cannot express — takes free, voices cost one batch per ~6. The phrasing is dense and some clauses (tempo_map vs duration_seconds precedence) require re-reading, which costs a point.

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 ('Estimate what a job will cost in credits') plus a second dimension (affordability), and immediately distinguishes itself from the sibling job tools via 'BEFORE submitting it' and 'Spends nothing'. An agent can tell this is a dry-run pricing call, not a job submission, without opening the schema.

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?

Gives clear when-to-use guidance: call before submitting, pass the same args you would give the job tool. The alternative (invoking the job tool directly, spending credits) is implied by 'Spends nothing' and 'BEFORE submitting'. It does not explicitly state when not to use it — e.g. that it can't replace the job tool itself or that doseedo_account is the place for balance history — so it stops short of full routing coverage.

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