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

Beyond the annotations (readOnlyHint=false, openWorldHint=true), it discloses that ingestion runs in the background (async), that two source types fail with 501 until released, and that a write-scoped key is required. These are exactly the behavioral traits an agent needs before calling a mutating tool.

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 tight sentences: action, endpoint mapping, then constraints. Constraints are front-loaded rather than buried, and no sentence is wasted.

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 an async mutation with no output schema and fully documented params, the description covers action, auth, and failure modes. It omits what success returns (e.g. an ingestion/job handle) and how it relates to add_sources, which an agent choosing between the two would want.

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%, so the baseline is 3, but the description adds genuine value about the `type` discriminator by explaining the runtime status of each value (video supported, document/website reserved with 501). channel_id and idempotency_key semantics are left to the schema.

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+resource ('Add a source to a channel') and even names the underlying endpoint, so the operation is unambiguous. It does not differentiate from the sibling add_sources, leaving the singular/plural distinction to be inferred.

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 real usage conditions: only type: video works today, document/website return 501, and the key needs write scope. It stops short of routing to alternatives such as add_sources for batch adds or get_status for polling ingestion.

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