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A2A live JSON-RPC A2A 0.3.0 v1.0.0

Postbye

postbye.com · Postbye

Postbye cancels subscriptions for you by mail.

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Conformance
49/100
grade D · 9 criteria
Uptime
not measured
no direct probes in 30d
Observed inflow · 30d
—
no payment wallet declared
Invocations · 7d
0
no calls observed
Card drift · 7d
stable
1 snapshot tracked
Owner
unverified
claim this listing →
D
Conformance score: 49/100
D-grade: significant issues, auth-gated, partially broken, or stale.
Show breakdown Hide breakdown

Declare your skills · 10 points available for skill declaration

pass Valid AgentCard 10/10
Parseable AgentCard returned by the well-known endpoint (Agenstry readiness signal; not an official TCK certification).
pass Live JSON-RPC 25/25
Endpoint responds to a negotiated A2A SendMessage probe.
partial Protocol version 5/10
Declares pre-1.0 A2A 0.3.0 (Google preview). Upgrade to v1.x for full points.
How to earn +5 points
Declare protocolVersion
Add `"protocolVersion": "1.0"` (Major.Minor, no patch number — §3.6) to every entry in `supportedInterfaces[]`. A2A v1.0 removed the AgentCard root field.
Docs
info JWS signature 0/10
Card is unsigned (most published agents are).
info Uptime track record 0/15
Only 0 probes so far, need ≥5 for an uptime grade.
fail Skill declaration 0/10
No skills declared in card. Hard to route to.
How to earn +10 points
Declare your skills
Add at least one entry to the `skills` array on the AgentCard, each with `id`, `name`, `description`, `tags` — `description` and `tags` are REQUIRED on AgentSkill since A2A v1.0, and tags are what discovery filters match on. We canonicalise these into the global skill taxonomy on next probe.
Docs
partial Verified Identity 5/10
Provider declared: Postbye (https://postbye.com/). Add a registry identifier (LEI, Companies House number, KvK, ABN, …) to provider.legalEntity for full verified-business credit.
How to earn +5 points
Verify your domain ownership
Claim your listing and add the DNS TXT record we generate. Alternatively, sign your card with a JWS key that resolves to a verified-business LEI / KvK / Companies House registration.
Docs
pass Freshness + modern flags 4/5
seen in upstream source within 0d
info Security declaration 0/5
Neither securitySchemes nor securityRequirements declared — how to authenticate is unstated.

Activity

last 24h · 0 invocations No personal data recorded

No activity in the last 7 days.

Card history

1 snapshot
Snapshots
Agent card snapshots
Captured Hash Snapshot
2026-11-14 01:15:32 current c2f78bea4df1… view →
Uptime
not measured
0 direct probes · 30d
Response
—
no direct probe retained
Skills
1
declared
Streaming
—
SSE-capable

Try it

Sent live, through Agenstry.

calling agent… ⌘/Ctrl + Enter

Endpoints

Agent cardhttps://postbye.com/a2a
Providerhttps://postbye.com/
Docshttps://postbye.com/mcp-server
Discovered via
a2aregistry

Health · last 0 probes

Probe log
When HTTP Live JSON-RPC Latency
No direct probes in the last 30 days.

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Embed a badge

Updates itself and links back here.

Agenstry grade Uptime A2A protocol version
[![Agenstry grade](https://agenstry.com/badge/postbye.com.svg)](https://agenstry.com/agents/postbye.com)
[![Verified Business](https://agenstry.com/badge/postbye.com/identity.svg)](https://agenstry.com/agents/postbye.com)
[![Uptime](https://agenstry.com/badge/postbye.com/uptime.svg)](https://agenstry.com/agents/postbye.com)
[![A2A version](https://agenstry.com/badge/postbye.com/protocol.svg)](https://agenstry.com/agents/postbye.com)

Audit evidence

JSON for vendor reviews. Signed copy verifies against our JWKS.

audit.json audit.json (JWS-signed) verification history
Raw agent card JSON
{
  "name": "Postbye",
  "url": "https://postbye.com/a2a",
  "description": "Postbye cancels subscriptions for you by mail.",
  "version": "1.0.0",
  "documentationUrl": "https://postbye.com/mcp-server",
  "iconUrl": null,
  "defaultInputModes": [
    "text/plain"
  ],
  "defaultOutputModes": [
    "text/plain",
    "application/json"
  ],
  "skills": [
    {
      "id": "company-lookup",
      "name": "Company cancellation lookup",
      "description": "Send message/send with a company name or slug as text (up to 500 characters). The reply is one message: a text summary of how the company takes cancellations, whether the facts were checked by hand and whether Postbye can mail a cancellation letter to it, plus a data part with the same public record. With no match it lists up to five close guides. Letter text and mailing addresses are in the MCP endpoint.",
      "tags": [
        "subscriptions",
        "cancellation",
        "lookup",
        "read-only"
      ],
      "examples": [
        "How do I cancel Netflix?",
        "Does Planet Fitness accept cancellation by letter?",
        "netflix"
      ],
      "inputModes": [
        "text/plain"
      ],
      "outputModes": [
        "text/plain",
        "application/json"
      ]
    }
  ],
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "stateTransitionHistory": false,
    "extensions": null
  },
  "protocolVersion": "0.3.0",
  "provider": {
    "organization": "Postbye",
    "url": "https://postbye.com/"
  }
}