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

Annotations already cover read-only/idempotent/non-destructive/closed-world, so the description's value is in the substantive caveat: 'Success validates recorded fields, not legal tax compliance' — a real expectation-setter about what a pass means. It also discloses the shape of the result (blockers plus a next_tool), which 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?

Three short sentences, no filler, with the core action and the result shape front-loaded. Every clause carries information the agent cannot get from structured fields.

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?

No output schema exists, so the description must signal return content — it does at a high level (blockers, next_tool) and flags the compliance caveat. It stops short of describing what a blocker entry looks like or the behavior on a failed check, which leaves a small gap.

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?

With schema coverage at 50%, the schema documents business_id (omit for own business; use businesses_list) but leaves invoice_id bare, and the description adds nothing about either parameter. Baseline 3 applies since the ambiguity that matters is already handled in the schema.

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 object: 'Check issuance readiness', returning blockers and their next_tool. It is clearly a pre-flight validation step distinct from invoice_issue, though the description itself never says 'invoice' — that only comes from the tool name and title.

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?

Usage is implied rather than stated: 'Read blockers and their next_tool' points at a follow-up chain, and 'ask the user for missing facts' tells the agent what to do with results. But it never says explicitly to call this before invoice_issue, nor when it can be skipped.

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