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

Discloses important behavioral details beyond annotations: ownership enforcement, deactivation instead of deletion, and that historical events remain accessible via recent_alerts. Aligns with annotations (readOnlyHint=false, destructiveHint=false) and adds value.

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, front-loaded with core action, followed by key constraints and side effects. No redundant or vague phrasing.

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 tool with one parameter and no output schema, the description covers purpose, usage constraints, and side effects comprehensively. Minor omission: no mention of error behavior or return value, but still adequate.

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% with a single parameter 'id' described as 'Subscription id (uuid) returned by subscribe.' The description does not add additional parameter semantics beyond what the schema provides, so baseline 3 is appropriate.

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?

Clearly states 'Cancel a subscription by id' with verb and resource. Differentiates from sibling tools like subscribe, list_subscriptions, and recent_alerts by specifying cancellation and ownership enforcement.

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 explicit ownership constraint ('you can only cancel your own subscriptions'), clarifying appropriate use. Does not explicitly state when not to use or compare to alternatives, but context is clear enough for decision-making.

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