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

Annotations only declare the generic profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false, openWorldHint=false). The description supplies non-obvious behavior: an `authenticated` id is created but cannot be signed by this connector so viewers cannot play it, and the call is refused with `code: stream_active` during live states because the live API would stop the broadcast. That is exactly the behavioral context annotations cannot carry.

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?

Four short, front-loaded sentences: action, preference, caveat, refusal mode. Every sentence carries distinct information (default choice, signing limitation, failure state, retry guidance) with no restatement of the schema or annotations.

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, so return values need not be explained, and both parameters are fully documented in the schema. The remaining agent-critical unknowns, the default policy and the stream-state refusal, are covered explicitly.

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 enum meanings are already documented in the schema, so the baseline is 3. The description adds decision-level meaning beyond the schema by recommending `public` as the default policy, which helps an agent choose between the two enum values.

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 ('Add a playback id') and pairs naturally with the sibling remove_playback_id, so an agent can tell what it creates versus deletes. It stops short of explicitly naming a sibling or contrasting scope, which keeps it from a 5.

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 an explicit default ('Prefer `policy: public` unless the user asked otherwise') and an explicit exclusion window: refused with `code: stream_active` while the stream is starting, waiting, launching, live, or idle, with an instruction not to retry until it is stopped. Both the when and the when-not are stated, which is what a 5 requires.

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