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

Beyond the annotations it discloses the credit valuation model (1 credit = $0.033 list per revealed prospect), the fact that over-budget situations produce a note, and that expectedMeetingsPerMonth is a pessimistic planning estimate rather than a guarantee. 'Pure computation — nothing is created or charged' is a materially useful safety statement; note that readOnlyHint=false is conservative relative to that claim, but destructiveHint=false is consistent, so this reads as clarification rather than contradiction.

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 purpose is front-loaded in the first clause and every subsequent sentence adds a distinct fact (credit pricing, budget-overrun note, estimate caveat, no-side-effects, positioning). The second sentence is long and packs output-field naming with the pricing model, which slightly reduces scanability but nothing is wasted.

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?

There is no output schema, so the description carries the return-value burden, and it largely does: it names the sizing outputs, the three cost fields, the credit basis and the meetings estimate. It leaves the exact shape of the over-budget note and the full output field set implicit, which is a minor gap for a tool with no structured return contract.

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 budgetUsd, platformUsd and maxMailboxes are already documented in the schema. The description adds meaning about output semantics (creditsUsd, recurringUsd, firstMonthUsd) rather than input semantics, and does not elaborate on how platformUsd is reserved or how maxMailboxes caps sizing beyond what the schema states. Baseline 3 is appropriate.

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?

Specific verb and resource: it converts a monthly dollar budget into a sized outbound setup, and enumerates the concrete outputs (domains, mailboxes, sending volume, prospects, setup/recurring/first-month costs). The closing line 'answers what does $X/month get me without starting a run' cleanly separates it from the run-execution siblings like start_autopilot_run.

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?

It gives a clear situational trigger ('what does $X/month get me') and an implicit exclusion (use this instead of starting a run when you only want sizing). It does not name a specific alternative tool, so an agent must infer that start_autopilot_run is the counterpart when it actually wants to execute.

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