A2A
live JSON-RPC
A2A 0.3.0
v1.0.0
Postbye
postbye.com
· Postbye
Postbye cancels subscriptions for you by mail.
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
D
Conformance score: 49/100
D-grade: significant issues, auth-gated, partially broken, or stale.
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 recordedNo activity in the last 7 days.
Card history
1 snapshotSnapshots
| 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.
Endpoints
| Agent card | https://postbye.com/a2a |
| Provider | https://postbye.com/ |
| Docs | https://postbye.com/mcp-server |
Discovered via
a2aregistry
Health · last 0 probes
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Audit evidence
JSON for vendor reviews. Signed copy verifies against our JWKS.
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/"
}
}