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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds real behavioral value on top: the ~50 s follow budget, what the non-wait path returns (recent messages with files and widgets, chat status, pending permission requests), and the underlying endpoints. It does not discuss auth or rate limits, but nothing here contradicts the annotations.

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?

Front-loaded with the one-line purpose, then the wait mode, then the default mode, then the endpoints — a sensible ordering with little filler. It is denser than it needs to be (the endpoint strings add little for an agent), but 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?

There is no output schema, so the description carries the return-value burden and does so for both modes: latest answer (or post-cursor events) for wait, and messages/files/widgets plus status and pending permission requests otherwise. Combined with annotations covering safety, an agent has everything needed to call it correctly.

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 wait, after, limit, before and chatId, including defaults and bounds. The description restates the wait/after interaction rather than extending it with new format or edge-case detail, so the baseline 3 applies.

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 ("Read a Muse chat") and immediately splits the behavior into the wait and non-wait modes, which lets an agent tell it apart from write-oriented siblings like muse_chat, muse_cancel_chat, or muse_delete_chat. It stops short of naming a sibling directly, so the differentiation is inferential rather than explicit.

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 explicit when-to-use guidance for the streaming path — "use this to get the rest of an answer still running" — and ties the after parameter to that scenario. It also implicitly frames the no-wait path as the general read case. What is missing is any explicit exclusion relative to siblings (e.g. when to prefer muse_list_chats or a poll loop instead).

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