mp_screenshot

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

With no annotations, the description carries full burden. It discloses that a screenshot is captured, active session is required, and output defaults to inline image or file save. However, it does not detail potential side effects or error conditions beyond the session prompt.

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 with no filler. The main action is first, followed by prerequisite and output behavior. Every sentence adds value.

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?

Given the tool's complexity (nested connection parameter, no annotations, no output schema), the description covers the core purpose and usage context but leaves the connection parameter unexplained. It references mp_ensureConnection but does not fully describe the connection setup.

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 0%, so the description must compensate. It explains the 'path' parameter (save to file) but provides no explanation for the complex 'connection' parameter. Users must rely on external knowledge or sibling tool mp_ensureConnection.

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 clearly states the tool's action: 'take a screenshot of the current mini-program viewport' (specific verb and resource). It distinguishes itself from siblings by focusing on screenshot capture, while other tools like mp_currentPage retrieve page info.

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?

Explicitly mentions the prerequisite of an active session and directs users to call mp_ensureConnection if none exists. This provides clear when-to-use and alternative step guidance.

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