Mariana Google MCP

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

No annotations provided, so description carries full burden. Adds valuable behavioral context by stating 'Returns full message content' (disclosing output granularity). However, missing auth requirements, rate limits, and whether this operation marks messages as read.

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 states operation, second states return value. Front-loaded and appropriately sized for 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?

Given simple 2-parameter structure, 100% schema coverage, and lack of output schema, the description adequately covers core functionality by mentioning the return value. Would benefit from auth scope or error handling mention, but sufficient for a read-only retrieval operation.

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 coverage is 100%, so schema already documents both parameters. Description references 'by ID' acknowledging the required parameter, but doesn't add syntax details, format constraints, or semantic meaning beyond what the schema provides. Baseline 3 appropriate for high schema coverage.

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?

States specific verb ('Read'), resource ('Gmail message'), and access pattern ('by ID'). Clearly distinguishes from sibling tools like gmail_search (which finds messages) and gmail_draft (which creates).

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?

Implies prerequisite (needing a message_id) by specifying 'by ID', suggesting prior use of gmail_search. However, lacks explicit guidance on when to use vs. alternatives or prerequisite steps.

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