channel_wait

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

With no annotations, the description carries the full burden and does so: it declares this is read-only and does not auto-ACK, describes timeout/cancel/connection-failure endings, warns that local-only client timeouts are invisible to the server, and even gives the MCP-request timeout formula (timeout_seconds + 4*io_timeout_seconds + 5). This is exactly the operational context an agent needs to invoke it safely.

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 tight paragraphs, front-loaded with purpose, then behavior, then the actionable timeout budget rule, then return/error semantics. Despite the density every sentence carries distinct information, so nothing reads as padding.

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 9-parameter blocking tool with no annotations but with an output schema, the description covers what the schema and output cannot: read-only guarantee, blocking lifecycle, cancellation/failure endings, timeout composition, and durable error behavior on bad cursors. Nothing an agent needs to call it correctly 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 coverage is 100%, so the baseline is 3, but the description adds real value: it explains how timeout_seconds and io_timeout_seconds compose into the caller's overall timeout budget, clarifies that cursor is the resume mechanism (not a timestamp), and states that an invalid cursor errors loudly rather than silently skipping pages.

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 opening clause states a specific verb (等待) and resource (指定对端的新消息) plus the mechanism (先补读, 随后 WebSocket), which cleanly separates it from poll-style siblings like channel_read / channel_unread / channel_mentions. An agent can tell this is a blocking subscription-wait tool 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?

It gives clear context on when the tool is appropriate (waiting for new peer messages, replay-then-subscribe) and important exclusions (cannot wake an already-finished Desktop turn, timeout does not auto-reopen the wait). However it never names a sibling alternative for the non-blocking case, so the routing guidance is implied rather than explicit.

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