PaperAgent — Send Physical Mail
dev.paperagent/letters
MCP Bill of Materials
A machine-readable inventory of what this server exposes and depends on: tools with their effects, transports, packages, findings and provenance (schema version 1.0). Third-party text in it is escaped. Also available from the REST API at /api/v1/servers/901732ea-8a62-468c-a85f-2e9311fc1cb9/mcbom.
MCP Bill of Materials
root{21}
schema_version: "1.0"
bom_format: "squatch-mcbom"
generator{3}
name: "squatch-mcp"
classifier_version: "rules_v1@2026-10-11.1"
unicode_version: "18.0.0"
server{7}
name: "dev.paperagent/letters"
title: "PaperAgent — Send Physical Mail"
description: "Mail one-off USPS letters from ChatGPT or Claude after you approve the preview and price. US only."
version: "0.1.0"
homepage_url: "https://paperagent.dev"
source: "official_registry"
upstream_status: "active"
publisher{4}
namespace: "dev.paperagent"
display_name: "dev.paperagent"
type: "registry_namespace"
status: "unclaimed"
organization: null
repository: null
packages[0]
transports[1]
0{5}
kind: "remote"
type: "streamable-http"
endpoint_url: "https://paperagent.dev/mcp"
endpoint_host: "paperagent.dev"
auth_type: "none"
auth{3}
type: "none"
authorization_servers[0]
scopes[0]
protocol{4}
era: "legacy"
negotiated_version: "2025-11-25"
supported_versions[0]
transport_type: "streamable-http"
tools[8]
0{9}
name: "create_draft"
title: "Create a Letter Draft"
effect: "WRITE"
effect_confidence: 0.902
capabilities[5]
0{2}
capability: "EMAIL"
confidence: 0.962
1{2}
capability: "FILE_ACCESS"
confidence: 0.85
2{2}
capability: "FINANCIAL_TRANSACTION"
confidence: 0.811
3{2}
capability: "PAYMENT"
confidence: 0.565
4{2}
capability: "PERSONAL_DATA"
confidence: 0.954
risk_severity: "HIGH"
fingerprint: "82833a8ecae39fd75454cc77e95ae7d0420a7a14ed1711090c9fa8d28e2b34e6"
input_schema_fingerprint: "6b580a0d0662c2b9131aed9ea5a2c7f199a3059e84f9a6bb4f19d73dbd294bec"
annotations{5}
title: "Create a Letter Draft"
readOnlyHint: false
destructiveHint: false
idempotentHint: false
openWorldHint: false
1{9}
name: "get_letter_status"
title: "Get Letter Status"
effect: "READ"
effect_confidence: 0.921
capabilities[0]
risk_severity: "INFO"
fingerprint: "35f6c6b2139b42e6c17493f5cae71b5efcafe0cd1d052a305e7fa634b6993501"
input_schema_fingerprint: "1b71fe6b01b1c42d04b41230da2bc6795ad63e2845471181d140bb117de5a901"
annotations{5}
title: "Get Letter Status"
readOnlyHint: true
destructiveHint: false
idempotentHint: true
openWorldHint: false
2{9}
name: "get_pricing"
title: "Get Letter Pricing"
effect: "WRITE"
effect_confidence: 0.603
capabilities[2]
0{2}
capability: "FINANCIAL_TRANSACTION"
confidence: 0.886
1{2}
capability: "PAYMENT"
confidence: 0.763
risk_severity: "HIGH"
fingerprint: "ae675b46497c16f6d041651a4afb5752d4a42b5b15158b1da404c37d4fac2c49"
input_schema_fingerprint: "93ab7499dc3c616f8db8780fed0d9f69270803cda913882ad2ef3943db8d7225"
annotations{5}
title: "Get Letter Pricing"
readOnlyHint: true
destructiveHint: false
idempotentHint: true
openWorldHint: false
3{9}
name: "list_letters"
title: "List Letters"
effect: "READ"
effect_confidence: 0.908
capabilities[0]
risk_severity: "INFO"
fingerprint: "a0e7750f273a5665e1960a7099596a4f898860aa149d783a88692e306ac39e4a"
input_schema_fingerprint: "97a8d5c03301bda8dd8fc6b1b3655b7ceb3371fcf35a3e63f78ddc7cb49b19a7"
annotations{5}
title: "List Letters"
readOnlyHint: true
destructiveHint: false
idempotentHint: true
openWorldHint: false
4{9}
name: "preview_draft"
title: "Preview a Letter Draft"
effect: "READ"
effect_confidence: 0.928
capabilities[3]
0{2}
capability: "EMAIL"
confidence: 0.914
1{2}
capability: "PAYMENT"
confidence: 0.565
2{2}
capability: "PERSONAL_DATA"
confidence: 0.66
risk_severity: "MEDIUM"
fingerprint: "fa0216ba37f8b4523034c186510a69f95a11a249cdea6ecb8f41a34ae15844f6"
input_schema_fingerprint: "2ece2829e6a40373d732f1627ae15f6b294429f724a0b92738b5375e4148a877"
annotations{5}
title: "Preview a Letter Draft"
readOnlyHint: false
destructiveHint: false
idempotentHint: true
openWorldHint: false
5{9}
name: "send_letter"
title: "Send a Physical Letter (USPS)"
effect: "WRITE"
effect_confidence: 0.822
capabilities[4]
0{2}
capability: "EMAIL"
confidence: 0.601
1{2}
capability: "FINANCIAL_TRANSACTION"
confidence: 0.738
2{2}
capability: "PAYMENT"
confidence: 0.76
3{2}
capability: "PERSONAL_DATA"
confidence: 0.711
risk_severity: "HIGH"
fingerprint: "ed3538505217988765f563cd3ed1cb11f04bc650091079d474a1921e9891d430"
input_schema_fingerprint: "011ed4f3de349375095f94f8b132dabbf0b1ec3880731b9b7b98ff872516e71e"
annotations{5}
title: "Send a Physical Letter (USPS)"
readOnlyHint: false
destructiveHint: true
idempotentHint: true
openWorldHint: true
6{9}
name: "update_draft"
title: "Update a Letter Draft"
effect: "WRITE"
effect_confidence: 0.902
capabilities[4]
0{2}
capability: "EMAIL"
confidence: 0.974
1{2}
capability: "FINANCIAL_TRANSACTION"
confidence: 0.811
2{2}
capability: "PAYMENT"
confidence: 0.565
3{2}
capability: "PERSONAL_DATA"
confidence: 0.968
risk_severity: "HIGH"
fingerprint: "9ddaef4504d5a2e5c24fd775cff424903550d4cd7e969a738a57ead41b67b44d"
input_schema_fingerprint: "34e739a60a65e5597bdd844827ea6008248e7642aa97735181af13fb1ade6f35"
annotations{5}
title: "Update a Letter Draft"
readOnlyHint: false
destructiveHint: false
idempotentHint: false
openWorldHint: false
7{9}
name: "validate_address"
title: "Validate a US Postal Address"
effect: "READ"
effect_confidence: 0.943
capabilities[1]
0{2}
capability: "PERSONAL_DATA"
confidence: 0.958
risk_severity: "LOW"
fingerprint: "0ed501480f402e113eb43b50a58613544328403c0f0c859a42cacb7821b68f2f"
input_schema_fingerprint: "5296a3274e3739ff5ab3bf7151a1051ad56a97bbd52f457b1a8a5a2f66d07629"
annotations{5}
title: "Validate a US Postal Address"
readOnlyHint: true
destructiveHint: false
idempotentHint: true
openWorldHint: true
resources[5]
0{4}
key: "ui://paperagent/letter-card.html?v=7"
kind: "resource"
mime_type: "text/html;profile=mcp-app"
fingerprint: "748f97eb8ea143358c0d0dac961919b4fb9e3cfafc08e97f273bdec8c50fe662"
1{4}
key: "ui://paperagent/letters-list.html?v=7"
kind: "resource"
mime_type: "text/html;profile=mcp-app"
fingerprint: "86ed6d222b00f2b0326cf48b0cd01e5df26f624ae32105aa3003eee2166cb42c"
2{4}
key: "ui://paperagent/pricing-table.html?v=7"
kind: "resource"
mime_type: "text/html;profile=mcp-app"
fingerprint: "59321410bda9beda9ed2d728ee79f5a12db5205d781cc8dd03f5f64146b75231"
3{4}
key: "ui://paperagent/status-timeline.html?v=7"
kind: "resource"
mime_type: "text/html;profile=mcp-app"
fingerprint: "682532d0bdc857d920242375e3f9f089d71880d8a67eac9a53ad192833f480bb"
4{4}
key: "ui://paperagent/{document}"
kind: "template"
mime_type: "text/html;profile=mcp-app"
fingerprint: "e875497566491abefb7b205664a0386e71718f50d23b5714ff92571e4e9e2395"
prompts[0]
extensions[1]
0: "io.modelcontextprotocol/ui"
data{6}
privacy_completeness: "not_provided"
data_categories[0]
ai_training: null
retention_policy: null
processing_regions[0]
subprocessors[0]
external_integrations[1]
0{3}
host: "paperagent.dev"
registrable_domain: "paperagent.dev"
source: "transport"
findings[10]
0{6}
check_id: "SQ-REPO-MISSING"
category: "provenance"
severity: "LOW"
title: "No source repository linked"
subject_type: "server"
subject_name: null
1{6}
check_id: "SQ-SERVER-AUTH-NONE-WRITE"
category: "authentication"
severity: "HIGH"
title: "State-changing tools available without authentication"
subject_type: "server"
subject_name: null
2{6}
check_id: "SQ-SERVER-INSTRUCTIONS-INJECTION"
category: "prompt_injection"
severity: "HIGH"
title: "Server instructions contain directives to the AI model"
subject_type: "server"
subject_name: null
3{6}
check_id: "SQ-TOOL-ANNOTATION-UNDERCLAIM"
category: "annotations"
severity: "MEDIUM"
title: "Annotations understate what the tool does"
subject_type: "tool"
subject_name: "get_pricing"
4{6}
check_id: "SQ-TOOL-CONCEALMENT"
category: "prompt_injection"
severity: "HIGH"
title: "Text asks the AI model to hide actions from the user"
subject_type: "tool"
subject_name: "get_letter_status"
5{6}
check_id: "SQ-TOOL-INJECTION-INSTRUCTIONS"
category: "prompt_injection"
severity: "MEDIUM"
title: "Instructions addressed to the AI model"
subject_type: "tool"
subject_name: "get_letter_status"
6{6}
check_id: "SQ-TOOL-INJECTION-INSTRUCTIONS"
category: "prompt_injection"
severity: "MEDIUM"
title: "Instructions addressed to the AI model"
subject_type: "tool"
subject_name: "get_pricing"
7{6}
check_id: "SQ-TOOL-INJECTION-INSTRUCTIONS"
category: "prompt_injection"
severity: "MEDIUM"
title: "Instructions addressed to the AI model"
subject_type: "tool"
subject_name: "list_letters"
8{6}
check_id: "SQ-TOOL-INJECTION-INSTRUCTIONS"
category: "prompt_injection"
severity: "MEDIUM"
title: "Instructions addressed to the AI model"
subject_type: "tool"
subject_name: "send_letter"
9{6}
check_id: "SQ-TOOL-RECIPIENT-REDIRECT"
category: "prompt_injection"
severity: "CRITICAL"
title: "Asks the AI model to change recipients or destinations"
subject_type: "tool"
subject_name: "update_draft"
trust{9}
registry_namespace: "verified_upstream"
publisher_identity: "unverified"
organization: "unverified"
domain: "unverified"
repository: "not_provided"
source_provenance: "unknown"
security_scan: "findings_detected"
privacy_transparency: "not_provided"
monitoring: "active"
provenance{4}
registry_name: "dev.paperagent/letters"
registry_content_sha256: "526b62d912739b68fb988d9cbe9c81143993976d284c270bbd02b38b6cc1dd41"
scan_snapshot_fingerprint: "e1d1ca5f732eedd3a231d1733970c94d61234e08f614016a9a77985c85b47f2d"
scanner_version: "1.0.0"
timestamps{4}
generated_at: "2026-11-15T20:54:46.914Z"
observed_at: "2026-11-12T10:21:51.278+00:00"
registry_published_at: "2026-10-18T20:35:11.797+00:00"
registry_updated_at: null