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

With no annotations, the description carries the full burden. It discloses triggers (allowance, wall, commercial terms changes), verification cadence, payload contents, and token requirements. It also notes that the token is the only way to update/delete a watch. It lacks details on retry behavior or failure handling, but otherwise provides strong 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?

The description is concise, front-loads the primary action, and every sentence adds essential detail—subscription purpose, webhook payload, limits, and token notice. No fluff or repetition.

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 has no output schema, but the description compensates by explaining exactly what the webhook receives (changed fields, current wording, verification date, source page). It also covers setup, limits, and token management. For a tool with only three parameters and no complex return structure, this is complete.

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 baseline is 3. The description adds meaningful context: it explains 'key' as a Pro license that unlocks all tools, and 'slugs' with a free-tier maximum of 3. The 'hook' parameter is partly explained by 'webhook URL' in the schema, and the description reiterates HTTP POST. This extra guidance elevates the score above baseline.

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 'Subscribe a webhook to verified free-tier changes,' using a specific verb and resource. It clearly distinguishes from the sibling 'get_free_tier_changes' by emphasizing subscription and webhook delivery rather than an on-demand fetch.

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: when continuous monitoring of free-tier changes is needed, with daily verification. It also states usage limits (max 3 tools free, Pro license unlocks everything) and the importance of keeping the token for updates/deletions. However, it does not explicitly mention alternatives or when not to use it, so it misses the top bar.

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