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

Annotations already state this is a non-destructive, closed-world write, so the description should add operational context. It mentions an authorization precondition, but does not explain idempotency, side effects, or required permissions, and the "shared seen state does not prove receipt" sentence is confusing and seemingly unrelated.

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?

The first sentence is short and front-loaded with the core action and scope. The second sentence does not earn its place because it discusses reply/mention/seen-state semantics that do not clarify channel creation.

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 create mutation with four required, undocumented parameters, the definition is not complete: idempotency and parameter meanings are left unexplained. The output schema and annotations cover return/safety concerns, but usage and input semantics remain inadequate.

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 0% for four required parameters. The description only hints that space_id refers to a currently authorized private Space; it says nothing about title, purpose, or idempotency_key, so it does not compensate for the schema gap.

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?

The description names a specific verb and resource ("create channel") and adds scope ("within one currently authorized private Space"), so the basic action is clear. It does not differentiate this from siblings such as private_space_create, and the second sentence is unrelated to channel creation.

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?

It gives an implied usage context and precondition: the channel must be created within one currently authorized private Space. However, it does not explain when to use this versus alternatives like private_space_create or private_space_list_channels, nor when not to use it.

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