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

The description is exceptionally transparent, disclosing: authentication requirements, phone verification step, 10/day SMS cap, webhook HMAC signing and one-time secret return, auto-disable after 10 consecutive failed runs, and the always-on feed behavior. These go far beyond annotations (readOnlyHint=false, idempotentHint=true, etc.) and provide critical operational context. No contradiction with annotations, including the idempotentHint, since the description does not explicitly state whether repeated subscribes create duplicates.

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 and front-loaded. It starts with the core purpose and return value, then breaks down supported types and delivery channels. Each sentence adds meaningful information—no filler, repetition, or fluff. Despite its length, it earns every word for a tool with nested objects and multiple behaviors.

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 no output schema, the description appropriately states 'Returns the new subscription id.' It also covers authentication prerequisites, all delivery channels (feed, email, sms, webhook) with specific details like phone verification and signing secrets, and operational limits (10/day cap, auto-disable). For a moderately complex tool with nested params, this description is completely sufficient for agent invocation.

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 description coverage is 100%, so baseline is 3. The description adds value by giving concrete examples for type-specific params (e.g., items:["5.02"] = officer change for sec_8k, topic:"fed" for polymarket_edge) and clarifes delivery semantics (email templated alert, sms must match verified phone, webhook signing secret returned once). This goes beyond a mere restatement of schema properties.

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. Returns the new subscription id.' This clearly identifies the verb (create), resource (subscription), and output. It distinguishes from siblings like list_subscriptions and unsubscribe by focusing on creation and returns. The enumeration of supported subscription types further clarifies scope.

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 the prerequisite 'Requires a Pipeworx OAuth account (anonymous + BYO cannot persist subscriptions)' and explains delivery channels including the always-on feed as an alternative to pull via recent_alerts. It does not explicitly name alternative tools for when not to subscribe, but the context is clear enough that the agent can decide appropriately. Lacks explicit exclusions, hence 4.

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