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

With no annotations, the description carries the full burden. It discloses a key behavioral trait: 'Updates the baseline to the new content.' However, it omits other relevant behaviors such as error handling (e.g., invalid watch_id) and does not state whether the update is reversible or idempotent. This is partial disclosure.

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 concise, with two sentences. The first sentence front-loads the core action and outcome; the second provides usage guidance. No redundant words or filler.

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 tool is simple with two parameters, but there is no output schema. The description vaguely says it 'report[s] whether it changed' without specifying the exact format (e.g., boolean, status string, or structured list). It also does not cover error scenarios. For a simple tool this is a moderate gap, but not severe.

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 only 50% (token has a description, watch_id does not). The description adds no parameter-specific information and does not compensate for the missing watch_id documentation. An agent may not know what watch_id refers to beyond inference from the tool name.

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 tool's action: 'Re-fetch a watched page and report whether it changed since the last check, with a short list of added/removed content lines.' This uses a specific verb (re-fetch/report) and resource (watched page), and clearly differentiates from siblings like create_watch and delete_watch.

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?

It gives explicit guidance on when to use: 'Call this every time you want the latest status (e.g. each run/heartbeat).' This provides clear context but does not explicitly mention alternatives or exclusions, though the sibling set makes the distinction obvious.

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