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

With no annotations, the description carries the full burden. It discloses the core behavior (append, non-destructive) and adds context about supported document types ('doc, word, note') and content format (HTML). However, it lacks details on error handling, permissions, or what happens if the document does not exist.

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 a single, focused sentence that front-loads the action and includes necessary qualifiers without any redundancy or filler. Every word contributes value.

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 two-parameter tool with no output schema and no annotations, the description is largely complete. It communicates the main action, content format, and safety guarantee. It could be enhanced by mentioning behavior when the document is not found, but this is a minor gap given the low complexity.

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 input schema provides complete descriptions for both parameters (100% coverage), so the baseline is 3. The description adds minimal extra meaning beyond noting that content is HTML, which is already in the schema. The parameter semantics are adequately served by the schema.

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 (append), the target (existing document), and the content type (HTML). It distinguishes itself from siblings by explicitly noting 'without replacing existing content,' which separates it from update_document and create_document.

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 provides clear context for when to use the tool: to add content to an existing document. It implicitly suggests use over update_document by noting no replacement, but it does not explicitly name alternatives or exclusion criteria.

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