Piloxa – Certified Mail

Price a certified letter

quote_certified_letter

Read-onlyIdempotent

Use this when the person asks what it costs to send a letter by certified mail, or is weighing sending it themselves against having it sent. Says what a USPS Certified Mail letter costs, before anything is prepared. Give the number of printed pages and the service, and it returns the exact all-in total the person would pay: printing, the envelope and the postage are included, and nothing is added at checkout. A one-page letter is $12.97 with USPS tracking, $15.97 with the Electronic Return Receipt, which is the default, $24.21 with the Evidence Pack, or $50.10 as a Deadline Notice. There is no account to create, no subscription and no minimum. This tool is READ ONLY: it prepares nothing, stores nothing, mails nothing and charges nothing, so it is safe to call just to answer "what would that cost". Use prepare_certified_letter once the person wants the letter sent. U.S. destinations.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`service`	No	CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). CERTIFIED_EVIDENCE is CERTIFIED_ERR plus the Evidence Pack: a Certificate of Mailing and 7 years of retention. CERTIFIED_DEADLINE is CERTIFIED_EVIDENCE plus a same-day First-Class copy and an unclaimed-letter warning. Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses.
`page_count`	No	Number of printed pages in the letter, 1 to 10, the most the printer accepts in one letter. Defaults to 1.

Output Schema

TableJSON Schema

Name	Required	Description
`total`	Yes	The same total, formatted for a person, e.g. "$16.17".
`mailed`	Yes	Always false: this tool never mails.
`charged`	Yes	Always false: this tool never charges.
`service`	Yes
`currency`	Yes
`page_count`	Yes
`total_cents`	Yes	The whole price in cents. Nothing else is added at checkout.
`evidence_pack`	No
`minimum_order`	No
`account_required`	No
`service_fee_cents`	No	The rest of the total: the Piloxa service fee, including the card cost.
`subscription_required`	No
`postage_and_print_cents`	No	The part that goes to printing and USPS.
`includes_printing_envelope_and_postage`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedSep 25, 2026

changedInput schema / properties / page_count / description

Previous value: -"Number of printed pages in the letter, 1 to 5, the most the printer accepts in one letter. Defaults to 1."New value: +"Number of printed pages in the letter, 1 to 10, the most the printer accepts in one letter. Defaults to 1."

Changed1 schema field changedSep 25, 2026

changedInput schema / properties / page_count / description

Previous value: -"Number of printed pages in the letter, 1 to 60. Defaults to 1."New value: +"Number of printed pages in the letter, 1 to 5, the most the printer accepts in one letter. Defaults to 1."

Changed3 schema fields changedSep 24, 2026

changedInput schema / properties / service / description

Previous value: -"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). CERTIFIED_EVIDENCE is CERTIFIED_ERR plus the Evidence Pack: a Certificate of Mailing and 7 years of retention. Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."New value: +"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). CERTIFIED_EVIDENCE is CERTIFIED_ERR plus the Evidence Pack: a Certificate of Mailing and 7 years of retention. CERTIFIED_DEADLINE is CERTIFIED_EVIDENCE plus a same-day First-Class copy and an unclaimed-letter warning. Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."

changedInput schema / properties / service / enum

Previous value: -[
-  "CERTIFIED",
-  "CERTIFIED_ERR",
-  "CERTIFIED_EVIDENCE"
-]New value: +[
+  "CERTIFIED",
+  "CERTIFIED_ERR",
+  "CERTIFIED_EVIDENCE",
+  "CERTIFIED_DEADLINE"
+]

changedOutput schema / properties / service / enum

Previous value: -[
-  "CERTIFIED",
-  "CERTIFIED_ERR",
-  "CERTIFIED_EVIDENCE"
-]New value: +[
+  "CERTIFIED",
+  "CERTIFIED_ERR",
+  "CERTIFIED_EVIDENCE",
+  "CERTIFIED_DEADLINE"
+]

Changed2 schema fields changedSep 23, 2026

addedOutput schema / properties / evidence_pack
```
Added value: +{
+  "type": "boolean"
+}
```

changedOutput schema / properties / service / enum

Previous value: -[
-  "CERTIFIED",
-  "CERTIFIED_ERR"
-]New value: +[
+  "CERTIFIED",
+  "CERTIFIED_ERR",
+  "CERTIFIED_EVIDENCE"
+]

Changed2 schema fields changedSep 22, 2026

changedInput schema / properties / service / description

Previous value: -"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."New value: +"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). CERTIFIED_EVIDENCE is CERTIFIED_ERR plus the Evidence Pack: a Certificate of Mailing and 7 years of retention. Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."

changedInput schema / properties / service / enum

Previous value: -[
-  "CERTIFIED",
-  "CERTIFIED_ERR"
-]New value: +[
+  "CERTIFIED",
+  "CERTIFIED_ERR",
+  "CERTIFIED_EVIDENCE"
+]

Changed1 schema field changedSep 19, 2026

changedInput schema / properties / service / description

Previous value: -"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (proof of who signed). Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."New value: +"CERTIFIED is Certified Mail with USPS tracking. CERTIFIED_ERR adds the Electronic Return Receipt (the record of who signed, kept when USPS reports it back). Defaults to CERTIFIED_ERR, the same default prepare_certified_letter uses."

AddedSep 13, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Beyond the annotations, the description explicitly states this tool is READ ONLY and 'prepares nothing, stores nothing, mails nothing and charges nothing.' It also clarifies pricing is all-inclusive with nothing added at checkout and that no account or subscription is needed, which is valuable 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.

Conciseness5/5

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

The description is front-loaded with the primary use case and pricing, then ends with the clear sibling routing to prepare_certified_letter. Each sentence earns its place, including the read-only safety note and the U.S.-destination scope, without redundancy.

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?

For a two-optional-parameter, read-only pricing tool with an output schema and rich annotations, the description covers the core use case, exact pricing behavior, defaults, exclusions, safety, and the sibling tool to use next. Nothing essential is missing for an agent to select and invoke it correctly.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3, but the description adds meaningful semantics by mapping each service enum to a concrete price and clarifying the default service. It also explains the all-in cost behavior relative to page_count and service, which goes beyond the raw schema descriptions.

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 states a specific verb and resource: it quotes the all-in cost of a USPS Certified Mail letter before anything is prepared. It also explicitly distinguishes this from prepare_certified_letter by explaining this tool only prices, not sends.

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

Usage Guidelines5/5

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

It gives explicit when-to-use guidance: when the person asks what certified mail costs or is deciding whether to send it themselves. It also names the alternative, prepare_certified_letter, and states the condition for switching to it: once the person wants the letter sent.

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

All Piloxa – Certified Mail tools Inspect

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