skylight_set_message_caption

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

Annotations already indicate this is a non-read-only, non-destructive mutation. The description adds the behavioral detail that it sets/changes a caption rather than creating or deleting content. It does not disclose overwrite behavior or require special permissions, but for a simple setter the annotation coverage carries part of the burden.

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 a single front-loaded sentence with no filler. It is appropriately short for a simple setter, though the ambiguity of 'message/photo' prevents a perfect score.

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?

The tool has three parameters with no descriptions and no output schema, yet the description only paraphrases the tool name. It omits the distinction between id and frameId and does not clarify whether this applies to messages, photos, or both. The description is not complete enough for confident invocation.

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%, and the description adds no parameter meaning. It never explains what 'id' refers to (message ID? photo ID?), what format 'caption' takes, or what 'frameId' does. With zero schema-level descriptions, this is a critical gap.

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 ('Set') with a concrete resource ('message/photo caption'), so an agent can tell what operation is performed. It does not explicitly contrast with sibling tools, but no close sibling exists for setting captions, so the purpose is clear enough.

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 description provides no guidance on when to use this tool versus alternatives like add_message_comment, like_message, or upload_photo. There are no stated conditions, prerequisites, or exclusions, so the agent must infer usage solely from the name.

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