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

Beyond the annotations (readOnlyHint=false, idempotentHint=true), the description adds critical behavioral nuance: the tool only sets the status and does NOT guarantee actual video, it is idempotent with respect to the later-arriving callback, and it fails on ended sessions. These are exactly the non-obvious behaviors an agent needs to know.

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 description is tightly structured with labeled sections (when to use, combination chain, pitfalls). Every sentence carries operational value: trigger condition, fallback context, verification steps, idempotence, video caveat, and ended-session restriction. There is no filler.

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 state-changing tool with no output schema, the description is complete: it covers the trigger, the required verification flow, the idempotence behavior, the misleading 'live' status risk, and the ended-session limitation. An agent has everything needed to invoke it correctly and to set post-invocation expectations.

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 both liveId and activityRef are already documented with sources (get_organizer_live, get_activity/get_signup_activity). The description adds no parameter-level detail, which is acceptable because the schema carries the full burden. Baseline 3 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 names a specific verb, resource, and scenario: manually setting a live session to LIVE when the push callback was lost. It clearly distinguishes itself from the normal callback path and from siblings like end_live_session by framing itself as the fallback '兜底' operation.

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 explicitly states when to use this tool (push stream is already running but viewers don't see it live), gives a verification chain with get_organizer_live, and notes an exclusion: ended sessions (live_ended) cannot be opened and require a new session. This leaves no ambiguity about when the tool applies.

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