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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real context beyond them: the result depends on payment type and returns an itemized cost profile, and implies the job must already exist. It doesn't cover failure modes (invalid or unsubmitted job id) or whether the quote expires.

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?

Two short sentences plus an endpoint path; the purpose and the workflow instruction are both front-loaded and nothing is redundant.

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 does tell the agent what comes back at a high level (postage, printing, fees) and why it matters. The main gap is the effects of coupon_code and details, which an agent may need to choose non-default values.

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 75%, so the baseline is 3. The description reinforces payment_type dependence and hints at the itemized breakdown, but says nothing about 'details' or 'coupon_code', the latter of which has no schema description at all and is therefore documented nowhere.

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?

Names a specific verb and resource ('exact cost of a created job') and enumerates the cost components (postage, printing, fees), which separates it from a generic cost lookup. It does not explicitly contrast with click2mail_estimate_cost, the most confusable sibling, but 'created job' versus an estimate carries implicit differentiation.

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 an explicit workflow cue: 'Read it before click2mail_submit_job', which is actionable sequencing advice. It doesn't say when to use this rather than click2mail_estimate_cost, nor any exclusions (e.g., job not yet created), so it stops short of full routing guidance.

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