beel_patch_recurring_invoice

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

Annotations already indicate this is a write operation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds crucial behavioral context: only present fields are updated, null clears fields, and the recipient survives lines changes. It also warns about fiscal guardrails, which is beyond annotation coverage.

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 well-structured with the core behavior stated first, followed by a warning block and a pointer to documentation. It avoids redundancy and keeps the key information accessible without excessive 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?

For a complex PATCH operation, the description includes the endpoint, fiscal guardrails, and references to docs for exhaustive rules. It does not cover return values (no output schema) or idempotency (handled by annotations), but the provided context is sufficient for an agent to call the tool correctly with the schema's guidance.

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 low (33%) at the top level, but the body's nested schema has extensive descriptions. The description adds the essential 'null clears' rule that governs how parameters in the body are interpreted, but it does not elaborate on individual fields. It compensates partially for the schema gap.

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 clearly states the tool 'Updates only the fields present in the body', naming the resource as 'recurring invoice' and giving the endpoint. It explicitly distinguishes behavior from a full update by noting the recipient survives changes to lines, making the purpose unambiguous even among sibling tools like beel_patch_invoice.

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 description implies usage for partial updates of recurring invoices and includes important prerequisites (read fiscal guardrails, call beel_docs_search for exhaustive rules). However, it does not explicitly contrast with alternative tools or specify when NOT to use it, leaving some inference to the agent.

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