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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds valuable behavioral context: the consequence that a source-less Watcher 'ingests nothing' and the recommendation to use watcher_delete instead. It also discloses that the operation is not metered and requires an account. No contradiction with annotations.

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 and front-loaded. The core purpose is in the first sentence, with two parentheticals adding essential guidance and prerequisites. Every sentence earns its place without fluff.

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 2-parameter tool with no output schema, the description covers the purpose, the side effect, the alternative tool, and account requirements. It does not describe the return value or error behavior, but that is a minor gap given the simplicity and available annotations.

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 100%, with both parameters (sourceId, watcherId) clearly described in the schema. The description adds no new parameter semantics beyond restating 'by source id' and confirming that sourceId refers to the source to remove. Baseline 3 is appropriate because 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 exactly what the tool does: 'Remove a source from a Watcher by source id.' It uses a specific verb and resource, and immediately differentiates from the sibling tool watcher_delete by warning that a source-less Watcher ingests nothing and that watcher_delete is usually preferred.

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 explicit usage guidance: 'A source-less Watcher ingests nothing — usually you want watcher_delete.' This tells the agent when NOT to use this tool and points to the correct alternative. It also notes 'Not metered' and the requirement for a free Prowlo account, which are relevant operational conditions.

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