add_bill_attachment

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

Annotations already indicate a mutation (readOnlyHint=false). The description adds supported file types but omits other behavioral details such as file size limits, overwrite behavior, error conditions (e.g., file not found), or permission requirements. It provides moderate additional context beyond annotations.

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 three sentences with no fluff. The first sentence states the core purpose, the second lists file types, and the third gives usage context. It is well-structured and front-loaded.

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?

The description covers file types and a common use case, but it lacks information about return values (e.g., attachment ID), potential failure modes, or how it differs from similar tools (e.g., add_invoice_attachment). Given the absence of an output schema, more detail on what the agent can expect after invocation would improve completeness.

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 100%, and the schema describes each parameter adequately (including env var fallback for organization_id). The description adds no parameter-specific information beyond what the schema provides, meeting the baseline.

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 action ('Upload a file attachment to a bill') and identifies the resource. It lists supported file types and suggests use cases ('vendor invoices or supporting documents'). However, it does not explicitly differentiate from sibling tools like add_invoice_attachment, which also attach files to documents.

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 includes 'Use this to attach vendor invoices or supporting documents,' providing some context. But it does not advise when not to use it (e.g., for invoice attachments) or compare with sibling tools. Usage guidance is implicit rather than explicit.

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