ACTION_SHARE

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

With no annotations, the description carries the full burden and does disclose the output variables (share_success, share_error), the EXTRA_TEXT-only limitation, ${var} interpolation, and that results come back as a variable snapshot JSON. It does not say whether the call blocks until the user picks a target or what happens if the share sheet is dismissed, which is the main remaining behavioral unknown for a UI-interactive action.

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 purpose is front-loaded in the first clause and the size is compact. There is minor redundancy ('只通过 EXTRA_TEXT…不附带文件；改 type 也发不了图片') and a doubled sentence terminator ('。。') that slightly hurts polish.

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 7-parameter UI action with no output schema, the description covers purpose, return variables, interpolation, and the key limitation, which is enough to call it correctly. Missing details are the blocking/await-user behavior and error-surface semantics beyond the listed variable names.

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 per-parameter meaning is already documented in the schema; the description only reinforces that string parameters accept ${var} and that 'type' does not enable image sharing. It adds nothing about 'require', 'on_error', 'node_timeout_ms', or 'subject', so it sits at the baseline for a fully-documented schema.

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 and resource ('分享文字：弹出系统分享面板') and immediately bounds the scope to text-only sharing, which no sibling tool covers. An agent can distinguish this from ACTION_MEDIA_CONTROL or ACTION_SEND_NOTIFICATION without opening the 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?

It gives clear conditions for use (share text via the system share sheet) and an explicit negative constraint: no file attachments, and changing 'type' will not make images shareable. There is no named alternative for the file/image case, so it stops short of full when/when-not/alternative guidance.

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