Get Space Stream URL

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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, and the description adds context beyond them: API key requirement, one request per call, ~1 unit cost, and that each result carries a cost estimate. The notable omission is URL lifetime/expiry, which matters for a stream URL an agent may pass on to a consumer.

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-loaded with the action and the required input source, then cost/auth facts. Every sentence carries information, though "Read-only." restates readOnlyHint=true and is mild redundancy.

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 one-parameter tool with a 100% covered schema and an output schema, the description covers the pieces that structured fields can't: upstream dependency, auth, and cost model. Only the stream URL's lifetime/expiry behavior is left unstated.

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% and the single parameter is already documented with its source, so the schema does the heavy lifting. The description only reinforces provenance of mediaKey and adds no format or validation detail beyond it — baseline 3 applies.

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 ("Fetch the audio stream URL for a Space") and names the sibling that produces the required input (tweetapi_space_by_id), so an agent can distinguish it from the other space/community tools without opening the schema.

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 concrete workflow guidance: the mediaKey must come from a tweetapi_space_by_id result, which establishes the prerequisite call ordering. It does not state when *not* to use it or what happens if the Space has ended, but the chaining context is the main ambiguity an agent would face.

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