get_stats

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

No annotations are provided, so the description carries full burden for behavioral disclosure. It does not state that this is a read-only operation, nor does it mention any side effects, authorization requirements, rate limits, or handling of edge cases (e.g., empty results, default window limits). The mention of 'created_at time window' gives some behavioral context, but the overall transparency is limited.

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 a single sentence that is concise and front-loaded with the core purpose ('Message counters of the server'), followed by a compact list of examples and the optional filter. No redundant words or restatements of the tool name, making it highly efficient.

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 tool's simplicity (two optional parameters, no output schema), the description covers the main functionality but omits details like return format, whether both parameters are required together, and handling of the time window. The absence of annotations leaves open questions about read-only status and expected output structure, making it adequate but not fully complete.

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?

The schema already provides 100% coverage with descriptions for both parameters (to and from as ISO 8601). The description adds meaningful context by clarifying that the window applies to 'created_at', which is not present in the schema. This helps the agent understand the semantic filter, going beyond the bare parameter definitions.

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 identifies the resource (message counters of the server) and the specific metrics included (sent, pending, bounced, opens, clicks), which conveys a retrieval purpose despite using a noun phrase rather than an explicit verb. It distinguishes itself from sibling tools like send_email and list_emails by focusing on aggregate counters rather than individual messages, but it does not explicitly contrast with list_bounces or dmarc_summary which might have overlapping concepts.

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 implies usage context: use this tool when you need aggregate message counters, optionally filtered by a created_at time window. However, it provides no explicit 'when to use this vs. alternatives' guidance, nor does it mention when not to use it (e.g., for detailed bounce lists, use list_bounces). The usage is inferred from the nature of the tool rather than explicitly stated.

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