读取实时事件快照

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the core non-blocking trait ('不等待', reads already-accumulated events), but says nothing about subscription validity requirements, the return shape of a 'snapshot', or behavior when no events exist.

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 tight sentences with the non-blocking core behavior front-loaded and the usage hint second. No waste, though it is arguably terse enough to leave gaps rather than being fully economical.

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 4-parameter read tool with no output schema and no annotations, the description covers the key non-blocking behavior but omits return-format expectations, what happens on an invalid/unknown subscription, and the meaning of includeFrameData. Adequate but with visible gaps.

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 only 50%: limit and cursor are documented in the schema, while subscriptionId and includeFrameData are documented in neither. The description adds no parameter-level meaning at all, leaving half the parameters (including the undocumented includeFrameData) unexplained.

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 specific verb (立即读取, read immediately) plus resource (订阅里已积累的实时事件, accumulated real-time events in the subscription) and explicitly contrasts with the blocking behavior of its sibling events_wait via '不等待'. An agent can distinguish this from events_wait without opening either 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?

The second sentence gives clear when-to-use context ('适合先看一眼再决定是否阻塞等待'), effectively pointing to events_wait as the blocking alternative. It stops short of naming the alternative tool explicitly, so it is strong but not fully spelled out.

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