view_media

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

With no annotations provided, the description carries the full burden and excels: it discloses image downscaling to max_dimension, GIF first-frame-only behavior, video mid-frame fallback, the local ffmpeg prerequisite, and error return format ('Chinese explanation'). This goes well beyond a simple 'view media' statement.

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 front-loaded with a one-sentence purpose, followed by well-separated sections for image vs. video behavior, tool differentiation, arguments, and return type. Every sentence earns its place; there is no fluff or repetition despite the detail.

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?

Despite lacking annotations and output schema, the description covers all needed context: return type (MCP ImageContent), error behavior, external dependency (ffmpeg), supported formats, scaling behavior, and runtime modes (stdio/HTTP). It also prevents misuse by referencing describe_video for animation/text needs, making it complete for both selection and 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 properties have no descriptions (0% coverage), but the Args section adds rich meaning: path is a local file path, timestamp is video-only and measured in seconds, max_dimension has a default (1024), range (16–4096), and behavior (shrink only, never enlarge). This fully compensates for the schema's silence.

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 opens with a specific verb+resource: 'return an image or a video frame as image content' to the calling model. It clearly distinguishes itself from the sibling tool describe_video by stating the division of labor: describe_video produces text, view_media returns the actual visual content.

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?

Explicit usage guidance is provided, naming describe_video as the alternative when a textual description is needed or when the whole GIF animation is required. It also clarifies when timestamp should be supplied for videos and the default behavior if omitted, making the decision boundary between tools unmistakable.

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