Validate a proposed email against the active local send policy before sending, without creating or sending anything. Read-only check to catch policy issues early.
Validate a proposed email against the active local send policy without creating or sending anything. Read-only.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | ||
| from | No | ||
| text | Yes | ||
| subject | Yes |
Changes observed during successful MCP inspections.
v0.6.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does disclose the most important trait — read-only, no creation, no sending — which is genuine value. But it says nothing about what a failed validation looks like, whether it returns a pass/fail or a list of policy violations, or how the 'active local send policy' is resolved, which matters for a tool with no output schema.
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 tight sentences with the action and its constraint front-loaded, no filler. 'Read-only' is slightly redundant with 'without creating or sending anything', but it is a cheap and useful emphasis rather than padding.
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 four-parameter, no-annotation, no-output-schema tool, the description covers the safety profile but not the result contract. Since there is no output schema, the description should indicate what a validation outcome looks like; that gap leaves the agent unsure how to interpret the response.
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 0% and the description mentions no parameters at all. It does not clarify that `from` is optional, nor that subject/text are length-bounded, nor that the message body goes in `text`. The field names are largely self-explanatory, but the description adds no meaning beyond them.
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?
Specific verb (validate) plus resource (a proposed email) plus the standard it is checked against (the active local send policy). It also negates the side effects of the nearest siblings (send_email, create_draft) with 'without creating or sending anything', so an agent can distinguish it from those tools without opening a schema.
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 context of use is implied — validate a draft before it is sent — and the description rules out side effects. However, it never says explicitly when to call this versus get_send_policy, queue_email_for_approval, or simply calling send_email, nor does it name an alternative, so the routing is left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.