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

Discloses rich behavioral details beyond annotations: one Watcher per sources entry, derived names, per-plan keyword limits, daily Reddit search behavior, non-metered status, and account/signup requirement. Annotations only say readOnlyHint=false and destructiveHint=false, so there is no contradiction.

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 dense but front-loaded with the core purpose, and each clause carries operational information. Parentheticals and dashes keep it organized, though it is longer than necessary; still, no sentence is 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?

For a two-parameter creation tool with no output schema, the description is comprehensive: it covers purpose, special keyword-monitor mode, default community behavior, per-source creation semantics, plan limits, metering, and account prerequisite. The agent has enough context to invoke correctly.

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 covers all 2 parameters with descriptions, so baseline is 3. The description adds valuable semantic context: the search query is passed via channel, subreddit is an alias that non-Reddit queries also use, and each sources entry maps to its own Watcher. This goes beyond the schema's field-level descriptions.

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 opens with 'Create Watchers', clearly identifying the action and resource. It distinguishes the keyword-monitor use case from community watchers and explicitly contrasts with keyword_monitor_create, making the tool's scope unambiguous relative to siblings.

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?

Provides concrete guidance: use platform 'reddit_search' with query as channel for keyword monitors, use keyword_monitor_create as the one-query shortcut, and understand that each sources entry creates its own Watcher. It also mentions plan limits and account requirements, helping the agent choose appropriately among siblings.

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