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

Annotations declare idempotentHint=true, but the description says 'Create... Returns the new subscription id,' implying each call creates a new subscription and is not idempotent. This directly contradicts the idempotentHint annotation, forcing a score of 1 per the rubric.

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 well-structured: it starts with the main purpose, then required account, then supported types and delivery channels. Every sentence carries necessary information for a complex tool with multiple subscription types and delivery options. It is lengthy, but the length is justified by the breadth of functionality.

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 tool with 3 params, nested objects, no output schema, and a variety of subscription types and delivery channels, the description covers all essential aspects: return value (subscription id), auth requirements, all supported types with examples, all delivery options with constraints, and even webhook failure behavior (auto-disabled after 10 consecutive failures). It is remarkably 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 value beyond the schema by providing concrete examples for each subscription type (e.g., items:["5.02"] = officer change, params:{topic:"fed"}), explaining delivery channel constraints (verified phone, 10/day cap, webhook HMAC signing), and detailing the always-on feed behavior. This goes beyond what the schema already describes.

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 a proactive monitoring subscription to a live-data event stream,' giving a specific verb and resource. It clearly distinguishes from sibling tools like unsubscribe and list_subscriptions by focusing on creation, and mentions 'Returns the new subscription id' to clarify the outcome.

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 states an explicit prerequisite: 'Requires a Pipeworx OAuth account (anonymous + BYO cannot persist subscriptions),' which tells users when not to use it. It also names an alternative for consuming alerts: 'pull via recent_alerts or GET registry.pipeworx.io/alerts.json,' giving clear when-to-use and when-not-to-use guidance.

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