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

Annotations only declare non-destructive and closed-world, but the description goes well beyond: it discloses that nothing is created or charged, that credits are valued at list price ($0.033) per revealed prospect, that a note fires when monthly cost exceeds budget, and that expectedMeetingsPerMonth is a pessimistic estimate rather than a promise. This is exactly the behavioral context annotations cannot convey.

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 description is longer than average, but it is front-loaded with the core purpose and every sentence earns its place: computation scope, pricing model, side-effect guarantee, estimate caveat, and sibling routing. Slightly dense, but complexity justifies the length.

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?

With no output schema, the description carries the burden of explaining return semantics — and it does so thoroughly, naming output fields (creditsUsd, recurringUsd, firstMonthUsd), what they value, the above-budget note behavior, and the caveat on expectedMeetingsPerMonth. For a pure-computation tool with fully documented inputs, nothing an agent needs is missing.

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 100%, so the schema already fully documents budgetUsd, platformUsd, and maxMailboxes including defaults and constraints. The description references 'monthly budget in dollars' which maps to budgetUsd but adds no per-parameter meaning beyond the schema; 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?

The description states a specific verb+resource pairing ('Turns a monthly budget in dollars into a concrete outbound setup') with a precise enumeration of what it computes. It explicitly differentiates itself from the sibling start_autopilot_run as a pre-flight planning step, so an agent can tell them apart without opening schemas.

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 final sentence gives an explicit usage directive — 'Use it to answer "what does $X/month get me" before start_autopilot_run' — naming both the trigger question and the sibling it precedes. The 'Pure computation' clause reinforces when to choose this over execution tools.

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