Create and retain an Actor communication channel

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

Annotations already flag readOnlyHint=false and destructiveHint=true, and the description adds substantially more: it writes live game/client state, requires confirm=true and explicit mutation approval, discloses the retention side-effect (stores the handle in getgenv().__mcp_comm_channels), specifies the reduced return surface, and gives failure guidance. This is well beyond what the annotations 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?

The critical warning is front-loaded and each clause carries real information (signature, phase/cost, requirements, verification, safety). It is dense rather than padded, though the 'On failure: inspect tool-schema...' boilerplate and the phase/cost tokens are template filler that dilute the signal slightly.

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 mutating tool with no output schema, the description covers the safety contract, preconditions, side effects, verification, and error path. It is close to complete; only explicit alternative-tool routing is missing.

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%, so the schema already documents name, confirm, and threadContext in detail. The description restates the signature and marks confirm as required, but adds no syntax, format, or constraint detail beyond the schema — the baseline 3 for full schema coverage is 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?

The description leads with a specific verb+resource ('WRITES LIVE GAME STATE', create_comm_channel) and states the exact effect: create a channel, retain it in getgenv().__mcp_comm_channels, and return only its serializable identifier/metadata. That distinguishes it cleanly from siblings like get-comm-channel and fire-comm-channel.

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 prerequisites (active-client, explicit-mutation-approval, confirm=true) and a verification step (assert-state), which implies when the tool is appropriate. But it never names the sibling alternatives (get-comm-channel, fire-comm-channel, run-on-actor) or states when-not to use this tool, so routing guidance is only partial.

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