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

Annotations already declare this as non-read-only, idempotent, and non-destructive. The description adds valuable operational details beyond these: it returns a new subscription id, requires authentication, mandates phone verification before SMS delivery, and enforces a 10/day SMS cap. It also clarifies that the feed is always enabled. No contradiction with annotations exists.

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 but well-structured with colons and parentheses, front-loading the action. Every sentence serves a purpose: purpose, return value, auth prerequisite, supported types, and delivery options. It could be slightly more readable with bullet points, but the length is justified by the tool's complexity.

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?

With 3 parameters, nested objects, and no output schema, the description covers the essential aspects: return value, prerequisites, subscription types, and delivery constraints. It works together with the schema to provide a complete picture. Minor gaps exist (e.g., error handling, idempotency details) but these are not required for a create tool with rich 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?

The input schema has 100% parameter coverage with descriptions, providing the baseline of 3. The description enhances this by giving concrete, type-specific examples like items:['5.02'] for sec_8k and topic:'fed' for polymarket_edge, which add semantic understanding beyond the schema's generic 'Type-specific filter' phrase. This illustrates how params map to real use cases.

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', a specific verb+resource phrase that unambiguously states the tool's function. It clearly distinguishes itself from sibling tools like list_subscriptions and unsubscribe by focusing on the creation action, leaving no doubt about its role.

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 context for when to use this tool: it requires a Pipeworx OAuth account, lists supported subscription types with example parameters, and explains delivery channels including the always-on feed and optional email/SMS. It references recent_alerts as an alternative for pulling the feed, implying a distinction between proactive (subscribe) and reactive (pull) monitoring. However, it doesn't explicitly state when not to use `subscribe` compared to other tools, hence not a 5.

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