startSubscription

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

With no annotations, description carries full burden. It discloses persistence, message accumulation, auto-close after 5 minutes, and support for multiple independent subscriptions. Additional details like authentication needs or reconnection behavior are omitted.

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?

Three concise sentences, front-loaded with the main action, no wasted words.

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?

Adequately covers the tool's purpose, lifecycle, and relation to other tools. Lacks details on error handling or output format, but given no output schema, this is acceptable.

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 covers all 4 parameters with descriptions. Description adds behavioral context (e.g., maxMessages buffer limit) but does not significantly enhance parameter meaning beyond what schema provides.

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?

Description clearly states it starts a persistent WebSocket subscription and returns a subscriptionId. It distinguishes from sibling tools like readMessages and stopSubscription by explaining the lifecycle, but does not explicitly differentiate from many subscribe* sibling tools.

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?

Implies usage pattern (start, read, stop) and mentions auto-close timeout, but does not provide explicit when-to-use or when-not-to-use guidance compared to alternative subscription methods.

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