Mariana Google MCP

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

With no annotations provided, the description carries full burden but only discloses query syntax behavior (the example). It fails to state whether this is read-only, what the return format is (message IDs vs snippets), pagination behavior beyond max_results, or any rate limits.

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 sentences with zero waste: first establishes purpose, second provides critical syntax guidance with example. Perfectly front-loaded and appropriately sized for the tool complexity.

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?

Adequate for the 3-parameter input schema, but since no output schema exists, the description should ideally mention what gets returned (e.g., message IDs, snippets) to complete the contract. Missing this creates ambiguity given the sibling gmail_read tool.

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?

While schema coverage is 100%, the description adds significant value by providing the concrete example 'from:name subject:topic', which clarifies the expected syntax for the 'query' parameter beyond the generic schema description.

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?

Description clearly states the specific verb 'Search' and resource 'Gmail messages', immediately distinguishing it from siblings like gmail_read (retrieve specific), gmail_draft (create), and gmail_move_to_delete (delete).

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?

Mentions 'Uses Gmail search syntax' which implies usage for filtering scenarios, but lacks explicit guidance on when to use versus gmail_read or whether search results need to be passed to other tools. No 'when-not-to-use' or prerequisite guidance provided.

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