Attach Source Document

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

Annotations already indicate readOnlyHint=false, destructiveHint=false, idempotentHint=true. The description adds that the tool can replace an existing document ('upload/replace'), which aligns with idempotent behavior. However, it does not elaborate on other behavioral aspects like authorization needs, file size limits, or what happens if the entity already has a document attached. The description is adequate but not rich beyond the 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 two sentences with no wasted words. It front-loads the action and resource, then provides essential business context. Perfectly concise for the complexity of the tool.

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 the core functionality and business context. Given that there is no output schema, the description does not need to explain return values. Minor gaps exist: it does not explicitly state that attaching a document replaces an existing one (though 'replace' is in the first sentence), and could mention file size or path accessibility. Overall, it is sufficiently complete for an agent to use the tool correctly.

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 100%, so the baseline is 3. The description does not add any additional semantic information about the parameters beyond what is already in the schema. For example, it does not clarify the meaning of 'absolute path' or the format of file_path. Since the schema already covers the parameter descriptions, the description provides no added value for this dimension.

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: 'Attach (upload/replace) a source document'. It identifies the resource type and lists acceptable entity types (purchase invoice, sale invoice, journal, bank transaction). It also provides business context (RPS requirement). This distinguishes it from sibling tools, which primarily deal with CRUD on other objects or document retrieval.

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 explains when to use: when a source document is needed on an accounting entry, as required by RPS. It mentions that manual journals and directly-booked transactions also need one. While it doesn't explicitly state when not to use or name alternative tools, the context is clear enough for an agent to decide. The sibling list includes get_document and delete_document, which are distinct operations.

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