Gemini MCP Server

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

With no annotations provided, the description carries full burden and does well: it discloses the async nature ('starts an async video generation'), timing expectations ('takes 1-5 minutes'), return value ('Returns an operation ID'), and workflow dependencies (polling with gemini-video-check). It doesn't mention rate limits or authentication needs, but covers key behavioral aspects.

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 well-structured and front-loaded: first sentence states core purpose, followed by timing/return info, then parameter list, then clear workflow steps. Every sentence earns its place with no redundant information. The bullet-point format for parameters and numbered steps for workflow enhance readability.

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 4-parameter tool with no annotations and no output schema, the description does well: it explains the async behavior, return format (operation ID), and polling workflow. It could mention error handling or rate limits, but covers the essential context for proper tool invocation given the complexity.

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 100%, so the baseline is 3. The description adds minimal value beyond the schema: it repeats parameter names and basic purposes but doesn't provide additional context about prompt best practices, aspect ratio implications, or resolution limitations. The 'from gemini-image' note for firstFrameBase64 is helpful but limited.

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 specific action ('Generate a video using Veo 3.1') and resource ('video'), distinguishing it from sibling tools like gemini-image (image generation) and gemini-video-check (polling). It explicitly identifies the model being used and the type of output.

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 explicit workflow guidance: 'Call gemini-video-generate → returns operationId', 'Wait 30-60 seconds', then 'Call gemini-video-check with operationId'. It names the specific alternative tool (gemini-video-check) for completion checking and explains the async nature of the operation.

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