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

With no annotations, the description carries the burden of behavioral disclosure. It clearly states the core behavior (append, not replace) but omits other behavioral traits such as required permissions, response format, or error behavior. This is a minimum viable disclosure: clear on the primary action but missing important context for a mutation tool.

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?

A single, front-loaded sentence that states its purpose and key constraint without any wasted words. Every element earns its place, covering action, resource, and nuance in one line.

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?

Given the simplicity of the tool (2 params, no output schema, no annotations), the description plus schema is nearly complete for invocation. It lacks notes on return values or failure modes, but these are minor for an append operation. The description covers the essential context: what to append, where, and to what.

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?

The schema covers 100% of parameters with descriptions, so the baseline is 3. The tool description does not add parameter-specific meaning beyond what the schema already provides (e.g., 'Document ID' and 'HTML content to append'), although the phrase 'to the end' reinforces content placement.

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 uses a specific verb ('Append'), names the resource ('existing document'), and clarifies scope with 'to the end' and 'without replacing existing content.' This distinguishes it from update_document and other sibling tools like create_document, making the purpose unambiguous.

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 when to use this tool (to add content without replacing) and even adds an explicit exclusion ('without replacing existing content'), which signals not to substitute it for update operations. However, it does not name alternative tools outright, so it stops short of full explicit guidance.

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