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

Annotations provide idempotentHint=true, openWorldHint=true, readOnlyHint=false. The description adds critical behavior beyond annotations: OAuth account requirement, phone verification prerequisite, 10/day SMS cap, webhook auto-disable after 10 consecutive failures, and one-time signing secret. 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 a single dense paragraph that packs significant detail without waste. Every sentence contributes value. While front-loading is good (purpose and return value first), the density could be slightly improved with structured formatting, but overall it is efficient and earns its length.

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 parameters (2 required, nested objects) and no output schema, the description is remarkably complete. It explains the return value (subscription id), all type options with parameter details, delivery channel options with constraints and behaviors, and prerequisites (OAuth, phone verification). No critical gaps remain.

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% but the description greatly expands meaning: provides type-specific parameter structures (e.g., sec_8k with items, polymarket_edge with topic and min_spread_bps, fred_series with series_id), explains delivery channel details (email, SMS with verification, webhook with HMAC signing and retry behavior), and adds examples. This goes well beyond the schema definitions.

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 starts with a specific verb-resource pair: 'Create a proactive monitoring subscription to a live-data event stream. Returns the new subscription id.' It clearly distinguishes from sibling tools like list_subscriptions, unsubscribe, and recent_alerts by focusing on creation. Examples of types and delivery channels further clarify the purpose.

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 usage context: requires a Pipeworx OAuth account, mentions persistence constraint for anonymous users, lists supported types with parameter examples, and explains delivery channels. However, it does not explicitly state when not to use this tool versus alternatives like ask_pipeworx or other monitoring tools, so it lacks explicit exclusions.

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