mailbox-mcp

list_outbound_mail

Read-onlyIdempotent

List outbound mail jobs with status tracking. Returns mail ID, recipient, mail class, status, cost, timestamps, and failure metadata. Filter by status, created_at date range, or search recipient/address/tracking/agent notes.

Instructions

Input Schema

TableJSON Schema

Name	Required	Description
`q`	No	Search recipient name, address lines, city/state/ZIP, tracking number, or agent notes.
`limit`	No	Maximum number of mail jobs to return (1-100). Defaults to 20.
`offset`	No	Number of mail jobs to skip for pagination. Defaults to 0.
`status`	No	Filter by mail status. "pending_approval" = awaiting human approval, "submitted" = queued for facility, "ready" = printed and ready to mail, "mailed" = in transit, "delivered" = confirmed delivery, "failed" = failure bucket, "cancelled" = cancelled before mailing. Use carrier_delivery_failed/failure_stage to identify mailed carrier delivery failures.
`test_mode`	No	Filter sandbox/test records. Defaults to the key environment for agent-scoped keys; member keys can pass true or false explicitly.
`created_after`	No	Filter mail created at or after this ISO 8601 datetime or YYYY-MM-DD date.
`created_before`	No	Filter mail created at or before this ISO 8601 datetime or YYYY-MM-DD date. Date-only values include the whole UTC day.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes	Outbound mail job summaries.

Schema Changelog

Changes observed during successful MCP inspections.

Changed30 schema fields changedv1.0.3Oct 12, 2026

addedInput schema / properties / created_after

Added value: +{
+  "description": "Filter mail created at or after this ISO 8601 datetime or YYYY-MM-DD date.",
+  "type": "string"
+}

addedInput schema / properties / created_before

Added value: +{
+  "description": "Filter mail created at or before this ISO 8601 datetime or YYYY-MM-DD date. Date-only values include the whole UTC day.",
+  "type": "string"
+}

addedInput schema / properties / q

Added value: +{
+  "description": "Search recipient name, address lines, city/state/ZIP, tracking number, or agent notes.",
+  "type": "string"
+}

changedInput schema / properties / status / description

Previous value: -"Filter by mail status. \"pending_approval\" = awaiting human approval, \"submitted\" = queued for facility, \"ready\" = printed and ready to mail, \"mailed\" = in transit, \"delivered\" = confirmed delivery, \"failed\" = delivery failed, \"cancelled\" = cancelled before mailing."New value: +"Filter by mail status. \"pending_approval\" = awaiting human approval, \"submitted\" = queued for facility, \"ready\" = printed and ready to mail, \"mailed\" = in transit, \"delivered\" = confirmed delivery, \"failed\" = failure bucket, \"cancelled\" = cancelled before mailing. Use carrier_delivery_failed/failure_stage to identify mailed carrier delivery failures."

addedInput schema / properties / test_mode

Added value: +{
+  "description": "Filter sandbox/test records. Defaults to the key environment for agent-scoped keys; member keys can pass true or false explicitly.",
+  "type": "boolean"
+}

addedOutput schema / properties / result / items / properties / carrier_delivery_failed

Added value: +{
+  "description": "True only when status=failed because a mailed/tracked carrier item later failed delivery.",
+  "type": "boolean"
+}

addedOutput schema / properties / result / items / properties / cost_breakdown

Added value: +{
+  "additionalProperties": true,
+  "description": "Authoritative cost components. For color jobs, color_printing_per_page_cents is the total color-page printing price (70 cents by published default), while color_surcharge_per_page_cents is the additive upgrade only (30 cents by published default). For a below-formula First-Class quote, first_class_baseline_adjustment_cents is the amount added to reach the published $2.00 one-page baseline and is separate from postage_cents.",
+  "type": "object"
+}

addedOutput schema / properties / result / items / properties / delivered_at

Added value: +{
+  "description": "Timestamp when delivery was confirmed, if available.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / document_preview_url

Added value: +{
+  "description": "Authenticated dashboard URL a human can click to visually verify the submitted source document.",
+  "format": "uri",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / error_message

Added value: +{
+  "description": "Failure reason when status is failed and a reason is available.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / failure_source

Added value: +{
+  "description": "fedex_tracking when FedEx Track reported the carrier delivery failure; null otherwise.",
+  "enum": [
+    "fedex_tracking",
+    null
+  ],
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / failure_stage

Added value: +{
+  "description": "carrier_delivery for carrier delivery failures; null for submission or fulfillment failures.",
+  "enum": [
+    "carrier_delivery",
+    null
+  ],
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / human_review

Added value: +{
+  "additionalProperties": true,
+  "description": "Human-readable review payload for CLI/chat confirmation: send-to address, return address, mail class, document preview URL, cost, safeguards, and next step.",
+  "type": "object"
+}

addedOutput schema / properties / result / items / properties / mailed_at

Added value: +{
+  "description": "Timestamp when the item entered the carrier/mail stream.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / recipient_city

Added value: +{
+  "description": "Recipient city.",
+  "type": "string"
+}

addedOutput schema / properties / result / items / properties / recipient_company

Added value: +{
+  "description": "Optional recipient company or organization line.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / recipient_country

Added value: +{
+  "description": "Recipient country code.",
+  "type": "string"
+}

addedOutput schema / properties / result / items / properties / recipient_line1

Added value: +{
+  "description": "Recipient street address line 1.",
+  "type": "string"
+}

addedOutput schema / properties / result / items / properties / recipient_line2

Added value: +{
+  "description": "Recipient street address line 2.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

changedOutput schema / properties / result / items / properties / recipient_name / description

Previous value: -"Recipient name."New value: +"Recipient name, or null when the mail is addressed to a company only."

changedOutput schema / properties / result / items / properties / recipient_name / type
```
Previous value: -"string"New value: +[
+  "string",
+  "null"
+]
```

addedOutput schema / properties / result / items / properties / recipient_state

Added value: +{
+  "description": "Recipient state.",
+  "type": "string"
+}

addedOutput schema / properties / result / items / properties / recipient_zip

Added value: +{
+  "description": "Recipient ZIP code.",
+  "type": "string"
+}

addedOutput schema / properties / result / items / properties / return_city

Added value: +{
+  "description": "Return address city.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_company

Added value: +{
+  "description": "Optional company or organization line for the return address.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_line1

Added value: +{
+  "description": "Return address street line 1.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_line2

Added value: +{
+  "description": "Return address street line 2.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_name

Added value: +{
+  "description": "Return address name.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_state

Added value: +{
+  "description": "Return address state.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

addedOutput schema / properties / result / items / properties / return_zip

Added value: +{
+  "description": "Return address ZIP.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

First observedv1.0.0Jun 15, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds valuable context by enumerating the returned fields (mail ID, recipient, mail class, status, cost, timestamps, failure metadata) and the filtering capabilities. This goes beyond the annotations and helps the agent understand what to expect from the response, especially the failure metadata which could be critical.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, front-loading the core purpose and immediately listing return fields and filters. There is zero filler or redundant information. Every sentence provides distinct information, making it efficient and easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given that an output schema exists, the return format is documented separately. Annotations cover the read-only/idempotent/destructive safety profile. The description covers the purpose, return fields, and filtering dimensions, which are the key operational aspects. Nothing an agent needs to call this tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all 7 parameters are thoroughly documented in the schema itself. The description summarizes the filters (status, date range, search) but does not add new semantics beyond what the schema already provides. The baseline of 3 applies since the schema does the heavy lifting, and the description adds marginal value by grouping related filters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description starts with 'List outbound mail jobs with status tracking.' This clearly states the verb (list), resource (outbound mail jobs), and purpose (status tracking). It distinguishes itself from sibling tools like get_outbound_mail (which implies single retrieval) and send_outbound_mail (creation). The specificity is high and unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains what the tool does and its filtering options, but it doesn't explicitly state when to use this tool versus alternatives like get_outbound_mail or list_inbound_mail. The usage context is implied but not contrasted with siblings. It provides no exclusions or explicit guidance on selecting this tool over others.

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

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