proforma_invoices_reject

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

The description adds a key behavioral consequence beyond the annotations: once rejected, the proforma cannot be converted to an invoice. This complements the idempotentHint and non-destructiveHint well. It does not mention authentication requirements or what happens if the proforma is already converted or rejected.

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 are front-loaded with the action, followed by optional inputs and the terminal consequence. Every sentence carries useful information with no repetition or filler.

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 simple state-change action with full schema coverage and useful annotations, the description covers the essential behavior: what it does, optional inputs, and the irreversible conversion consequence. Missing details about error states (already rejected/converted) and permissions are minor given the annotations.

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 already 100%, so the schema documents all four parameters. The description notes that rejection reason and notes are optional, but it does not clarify the distinction between the client-provided reason and internal notes that the schema defines, so it adds only marginal value.

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 and resource ('Mark a proforma invoice as rejected by the client') and clarifies that the rejection is client-driven. It does not explicitly differentiate this from sibling actions like proforma_invoices_cancel or proforma_invoices_delete, leaving some ambiguity among state-changing siblings.

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 by the client-rejection framing and the consequence that conversion becomes impossible. However, there is no explicit guidance on when to use this versus proforma_invoices_cancel, proforma_invoices_accept, or proforma_invoices_delete, so the agent must infer the choice.

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