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

Annotations already establish the safe read-only profile, but the description goes beyond them by disclosing the exact response body (`stream.id`, `stream.stream_key`, `stream.ingest`) and what is absent. It also flags a security-sensitive handling rule (do not place the key in another tool argument), which the annotations do not convey.

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?

Front-loads the return value and its purpose in the first sentence, then adds sibling differentiation, response composition, and handling constraints in tight succession. Every sentence contributes a distinct fact without padding.

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?

An output schema exists, and the description still usefully summarizes the return shape and its omissions. Combined with the security handling note and sibling routing, an agent has everything needed to call this correctly and use the result safely.

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% for the single `stream_id` parameter, so the schema already carries the parameter meaning. The description adds no syntax or format detail beyond what the schema provides, making baseline 3 appropriate.

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?

States a specific verb and resource ('Return `stream_key`') and names the exact consumer context (OBS or ffmpeg). It explicitly distinguishes itself from siblings by noting it is 'the only live tool that returns the key' and points to `get_live_stream` for everything else.

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?

Gives explicit when-to-use (need the key for OBS/ffmpeg) and when-not-to-use (status, playback, DVR belong to `get_live_stream`). It also adds operational guidance: give the key with the ingest URL and never pass it into another tool argument.

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