Extract the newest one-time verification code or confirmation link from inbound mail. Ideal for signup and login flows.
| Name | Required | Description | Default |
|---|---|---|---|
| token | No | Mailbox bearer token (mi_live_...) returned when the inbox was purchased. Optional when the MCP request itself carries Authorization: Bearer. | |
| sender | No | Only consider senders whose address contains this substring. | |
| inbox_id | Yes | Inbox UUID. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description indicates read-only behavior (extract from mail, newest) without annotations. It does not disclose important traits like whether the operation consumes/destroys the code, authentication requirements beyond the token parameter, or what happens if no code is found. With no annotations, the description carries the full burden and provides only basic behavioral context.
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: first states the core action and object, second gives ideal use cases. Extremely concise, front-loaded, and every word earns its place. No redundancy or irrelevant details.
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 3 parameters (1 required), no output schema, and no annotations, the description explains the tool's unique purpose versus siblings (e.g., get_message). However, it does not specify what the tool returns (the code/link text? the full message?) or behavior on failure (e.g., no verification code found). Mostly complete but could clarify return format.
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%—all three parameters have descriptions, so baseline is 3. The description adds purpose context (e.g., 'newest verification code') but does not elaborate on parameter semantics beyond what the schema already provides (token optional, sender filter, inbox_id required). No additional value given.
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 uses a specific verb ('Extract') and a clear resource ('one-time verification code or confirmation link from inbound mail'). It distinguishes itself from siblings like get_message and list_messages by focusing on extraction of a specific type of content (codes/links) from mail, and specifies 'newest' which adds precision.
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?
Explicitly states 'Ideal for signup and login flows,' providing clear context for when to use it. However, it does not explicitly exclude other scenarios or mention alternatives (e.g., use get_message for full message retrieval), but the sibling context makes such distinctions implicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct resource or action: create vs. delete vs. get for inboxes and webhooks, list vs. get for messages, plus specific actions like extracting verification codes, replying, and retrieving service info. There is no functional overlap.
All tool names follow a consistent verb_noun pattern in snake_case (e.g., create_inbox, get_verification_code, set_webhook). The naming is predictable and uniform across the entire surface.
With 11 tools covering inbox lifecycle (create, read, delete), message retrieval and actions (list, get, reply, verification code), webhook management (set, get, delete), and service information, the count is well-scoped for a temporary email service.
The tool surface provides full CRUD for inboxes, message retrieval and reply, webhook management, and specialized operations like verification code extraction. No obvious gaps exist for the stated purpose of managing disposable inboxes.
