MCP Email Service

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the dependency on cached data ('Works only after emails have been synchronized to the cache'), which is useful context. However, it lacks critical behavioral details: it doesn't specify if this is a read-only operation, what the output format looks like (no output schema exists), whether it's computationally intensive, or if there are rate limits. For an analytical tool with zero annotation coverage, this is a significant gap.

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 appropriately sized and front-loaded: the first sentence states the core purpose, and the second adds crucial usage context. Both sentences earn their place by providing essential information without redundancy or fluff. It's efficient and well-structured for quick comprehension.

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 the complexity (analytical tool with 4 parameters) and the absence of both annotations and an output schema, the description is moderately complete. It covers the purpose and a key prerequisite, but lacks details on behavioral traits (e.g., read-only status, performance) and output format. Without an output schema, the description should ideally hint at return values, but it doesn't. This leaves gaps that could hinder an agent's effective use.

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%, with all parameters well-documented in the input schema (e.g., 'Account ID to analyze (optional, default: all accounts)'). The description adds no parameter-specific information beyond what the schema provides. According to the rules, when schema coverage is high (>80%), the baseline score is 3 even with no param info in the description, which applies here.

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 tool's purpose: 'Analyze contact frequency and communication patterns using the local sync database.' It specifies the verb ('analyze') and resource ('contact frequency and communication patterns'), and distinguishes it from siblings like get_contact_timeline or list_emails by focusing on analytical aggregation rather than raw data retrieval. However, it doesn't explicitly differentiate from all potential analytical siblings (none are listed), keeping it at 4 rather than 5.

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 clear context for when to use the tool: 'Works only after emails have been synchronized to the cache.' This indicates a prerequisite (sync completion) and implicitly suggests alternatives like sync_emails or get_sync_health if data isn't ready. However, it doesn't explicitly state when NOT to use it (e.g., for real-time analysis) or name specific alternatives for overlapping functions, preventing a score of 5.

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