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 discloses that the session is already established at return time, that push_screen can pre-deliver cards to users who have not yet opened the link, that content is back-filled on open, and that chat/tracking are attributed to the same session_id. That is substantive behavioral context beyond the schema.

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 purpose, then parameters, then return value and the deferred-push workflow, so an agent can stop reading at any level. It is dense and slightly long, but nearly every clause adds actionable information rather than repeating the schema.

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, yet the description explicitly states the return payload {url, session_id}, instructs the agent to persist session_id, and explains the session lifecycle across push_screen and get_session_log. Nothing required to call it correctly appears to be 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 meaning: it flags slug as required, marks hostUserId as 'strongly recommended' because session ownership and offline re-push depend on it, and explains that app selects the canvas page (aicare-kf). This goes beyond the terse 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?

Starts with a specific verb+resource: generating a canvas link plus a session ID for a position, and immediately scopes it ('when the user needs a visible interface'). It is clearly distinguishable from siblings like push_screen and get_session_log, which it names as downstream consumers rather than alternatives.

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 a concrete trigger condition ('用户需要看得见的界面' – viewing reports/commodities/doing detection) and clarifies the ordering relationship with get_session_log and push_screen. It does not state explicit exclusions or when another sibling should be preferred instead, so it stops short of a 5.

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