read session

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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description need not explain safety. Beyond that it adds nothing behavioral: it does not say how the history is ordered, how pagination via before behaves, whether the sessionId alias conflicts with session, or what happens when an unknown index is given (the tool runs in a closed world).

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?

Two short sentences, and the core purpose comes first. Every clause carries information, with no filler or repetition.

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?

This is a five-parameter tool with no output schema, so the description should at least sketch the returned messages and the pagination contract. It covers only the purpose and the session-value format, leaving the return shape and the before/limit interaction to inference.

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 every parameter is documented, and 3 is the baseline. The description does add one thing beyond the schema: it states the ID format (mvs_*) and that a list index is accepted, but it never explains sessionId vs session, or what before anchors to, so it adds little beyond the schema descriptions.

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 states a concrete verb and resource: read the historical messages of a specified session (读取指定会话的历史消息). That is clear enough to separate this tool from list_sessions or send_message, but it never names its closest siblings (minimax_search, minimax_tail_sessions, minimax_events), so the agent has to work out which one retrieves history.

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?

There is no when-to-use guidance: nothing says whether to prefer this tool when tailing recent activity or when searching across sessions. The only guidance is what value the session parameter accepts, which is about parameters, not usage.

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