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

With no annotations, the description carries the full burden and discloses key behaviors: append semantics (doesn't touch existing), creation on missing file, a side effect (fires file_write webhook), and the return shape. It could mention authentication requirements or conflict behavior, but the schema covers api_key and if_match. This is solid transparency.

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?

Two sentences with zero waste: the primary behavior is front-loaded, followed by the alternative, a use case, a side effect, and the return value. Every sentence earns its place and the structure is optimal for quick comprehension.

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 tool with a rich schema and no output schema, the description is nearly complete: it covers behavior, alternatives, side effects, and return shape. It doesn't explicitly state error conditions or auth prerequisites, but the schema covers api_key, and the use case is clear. Nothing critical is missing for correct invocation.

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%, so the schema already documents all five parameters thoroughly. The description adds minimal parameter insight beyond stating 'append as a new entry', which matches the content parameter. Baseline 3 is appropriate since the schema does the heavy lifting.

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 states a specific verb and resource ('Append one entry to a file') with explicit constraints (doesn't touch existing content, creates if missing) and distinguishes itself from aanet_write_file by naming the alternative. This makes the tool's purpose unambiguous and differentiates it from sibling tools.

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 explicitly tells the agent when to use this tool versus aanet_write_file ('use aanet_write_file instead when you need to replace the whole file') and provides a typical use case (shared log or running notes). This is clear, actionable guidance with an alternative named.

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