DNS-AID

DNS-based Agent Identification and Discovery

Reference implementation for IETF draft-mozleywilliams-dnsop-dnsaid-02.

DNS-AID enables AI agents to discover each other via DNS, using the internet's existing naming infrastructure instead of centralized registries or hardcoded URLs.

Relationship to IETF

The DNS-AID specification is being developed within the IETF: https://datatracker.ietf.org/doc/draft-mozleywilliams-dnsop-dnsaid/.

This repository provides a reference implementation.

This project does not define the specification. The IETF draft is authoritative.

Scope of this Repository

This project focuses on implementation, tooling, and ecosystem activities.

Changes to protocol behavior should be discussed within the IETF.

New to DNS-AID? Start with the Getting Started Guide for install, first agent publication, and backend setup.

Documentation

• Getting Started Guide — install, first agent publication, backend setup
• API Reference — Python SDK, CLI, and MCP server tool reference
• ARD ai-catalog discovery — interop with Agentic Resource Discovery: catalog discovery, the host-anywhere DNS pointer, and card dereferencing
• Architecture — protocol layers, metadata resolution, integration points
• Integrations — backend-specific setup notes
• Demo Guide — end-to-end walkthrough for talks and presentations
• Roadmap — where the project is headed, near/medium/long term
• Privacy Policy | Security Policy | Trademarks

Ecosystem and Integrations

DNS-AID is a substrate. The library in this repository is sufficient on its own — it publishes and resolves agent records against any DNS provider, with no dependency on a particular directory, indexer, or telemetry backend.

When a search, indexing, or telemetry layer is useful, the SDK can point at any HTTP endpoint that implements the documented interfaces. Operators are encouraged to run their own — the indexer is a thin layer over the same DNS records this library publishes and discovers, and the SDK telemetry sink is configurable via DNS_AID_SDK_HTTP_PUSH_URL (off by default). Independent directory implementations exist across the ecosystem; DNS-AID is designed to remain interoperable with any of them rather than canonicalize a single one.

Quick Start

Install

# Install from PyPI
pip install "dns-aid[cli,mcp]"

# Or install the latest unreleased main from GitHub
pip install "dns-aid[cli,mcp] @ git+https://github.com/dns-aid/dns-aid-core.git"

For backend-specific extras (route53, cloudflare, ns1, cloud_dns, infoblox, akamai-edgedns, ddns), see the Getting Started Guide.

Python Library

import dns_aid

# Publish your agent to DNS
await dns_aid.publish(
    name="my-agent",
    domain="example.com",
    protocol="mcp",
    endpoint="agent.example.com",
    capabilities=["chat", "code-review"]
)

# Discover agents at a domain (Path A: DNS substrate)
agents = await dns_aid.discover("example.com")
for agent in agents:
    print(f"{agent.name}: {agent.endpoint_url}")

# Discover via HTTP index (richer metadata; format aligns with the ANS schema) —
# also auto-detects and dereferences ARD ai-catalogs (see docs/ard-catalog.md)
agents = await dns_aid.discover("example.com", use_http_index=True)
# (0.26.3+) A catalog on your own domain needs nothing. An off-domain catalog
# pointer is trusted only via per-record JWS (verify_signatures=True) or, opt-in,
# a DNSSEC-validated pointer (trust_dnssec_pointers=True) — otherwise it is ignored
# and discovery falls back to the on-domain catalog. The trust basis is surfaced as
# AgentRecord.catalog_trust (tls_domain | dnssec | jws). See docs/ard-catalog.md.

# (0.26.4+) Opt-in DNSSEC/DANE hardening (SDK/CLI/MCP; all default off — DNSSEC is
# never required). require_dnssec / min_dnssec enforce the resolver AD flag on
# DNS-plane agents (ARD / HTTP-catalog agents are exempt — they carry no DNS SVCB
# record). verify_dane binds each agent endpoint's TLS cert to its DANE/TLSA record
# (defense-in-depth, meaningful only under DNSSEC) → AgentRecord.dane_verified.
# (0.26.5+) trust_dnssec_pointers (above) is exposed the same way — CLI
# --trust-dnssec-pointers / MCP — so all four opt-in trust controls have SDK/CLI/MCP parity.

# Filtered discovery — pure-Python predicates over the in-memory result (v0.19.0+)
result = await dns_aid.discover(
    "example.com",
    capabilities=["payment-processing"],
    auth_type="oauth2",
    realm="prod",
    require_signed=True,
    require_signature_algorithm=["ES256", "Ed25519"],
)

# Verify an agent's DNS records
result = await dns_aid.verify("my-agent.example.com")
print(f"Security Score: {result.security_score}/100")

Path B: cross-domain search via an external directory (v0.19.0+)

When the caller does not yet know which domain hosts the agent it wants, the SDK can query any directory backend that implements the search endpoint. The directory layer is opt-in convenience; the DNS substrate remains the authoritative trust gate.

from dns_aid.sdk import AgentClient, SDKConfig

# Point at whichever directory the caller has chosen to trust.
# Can also be set via DNS_AID_SDK_DIRECTORY_API_URL.
config = SDKConfig(directory_api_url="https://your-directory.example.com")

async with AgentClient(config=config) as client:
    response = await client.search(q="payment processing", protocol="mcp")
    for r in response.results:
        print(r.agent.fqdn)

After the directory returns candidates, re-resolve each one through Path A and validate signatures / DNSSEC before invoking. This is the substrate-as-authority pattern: the directory provides ranking and discovery convenience, but never sits in the trust path between the caller and the agent.

async with AgentClient(config=config) as client:
    response = await client.search(q="fraud detection")
    for candidate in response.results:
        verified = await dns_aid.discover(
            candidate.agent.domain,
            name=candidate.agent.name,
            require_signed=True,
        )
        # Invoke only when DNS substrate confirms the directory's claim.

The SDK exposes additional filter parameters (capabilities, min_security_score, verified_only, etc.) for directories that compute and return those signals; see API Reference for the full surface. The semantics of those values are defined by whichever directory the caller has chosen — DNS-AID does not centralize them.

SDK: Invoke Agents & Capture Telemetry (v0.6.0+)

import dns_aid

# Discover + invoke in one line — telemetry captured automatically
result = await dns_aid.discover("example.com", protocol="mcp")
agent = result.agents[0]

resp = await dns_aid.invoke(agent, method="tools/list")
print(f"Latency: {resp.signal.invocation_latency_ms}ms")
print(f"Status:  {resp.signal.status}")
print(f"Tools:   {resp.data}")

# Rank multiple agents by your own local telemetry signals
ranked = await dns_aid.rank(result.agents, method="tools/list")
for r in ranked:
    print(f"{r.agent_fqdn}: score={r.composite_score:.1f}")

OpenTelemetry (v0.23.0+): install dns-aid[otel] and set otel_enabled=True (or DNS_AID_SDK_OTEL_ENABLED=true) to emit spans + metrics per invoke and propagate W3C trace context to downstream agents. See docs/integrations/opentelemetry.md.

For advanced usage (connection reuse, OpenTelemetry export, pluggable telemetry sink):

from dns_aid.sdk import AgentClient, SDKConfig

config = SDKConfig(
    otel_enabled=True,         # Export to any OpenTelemetry collector
    caller_id="my-app",
    # Optional: push telemetry to any HTTP endpoint the caller controls
    # http_push_url="https://your-telemetry.example.com/v1/signals",
)

async with AgentClient(config=config) as client:
    resp = await client.invoke(agent, method="tools/call", arguments={...})
    fqdns = [a.fqdn for a in agents]
    ranked = client.rank(fqdns)  # Rank by the caller's own observed telemetry

If an external aggregator publishes community-wide rankings over HTTP, the SDK can fetch them via client.fetch_rankings(...); the endpoint is configured by the caller, not by the library.

SDK: Per-Invoke Credential Provider Callback (v0.21.0+)

For short-lived credentials (RFC 8693 token exchange, AWS STS assume-role, HashiCorp Vault dynamic secrets, HSM/KMS-backed signing keys), pass an opt-in async credential_provider callback to invoke(). The SDK awaits the callback lazily at invoke time with the target AgentRecord and uses the returned dict for auth resolution. Strictly additive — every existing call site continues to work without source change.

async def token_exchange_provider(agent: AgentRecord) -> dict[str, str]:
    # Mint a fresh delegation token per call — e.g., RFC 8693 token exchange
    # against Keycloak / Okta / Auth0 / Microsoft Entra ID.
    return {"token": await my_idp.exchange_token(subject_token, agent.fqdn)}

async with AgentClient(config=config) as client:
    resp = await client.invoke(
        agent,
        method="tools/list",
        credential_provider=token_exchange_provider,
    )

Precedence: auth_handler > credentials > credential_provider > no_auth. See docs/security-credentials.md for the per-handler security matrix, audit-trail flow, and the examples/integration_oauth2_token_exchange.py and examples/integration_aws_sts_assume_role.py canonical patterns.

CLI Usage

# Publish an agent to DNS
dns-aid publish \
    --name my-agent \
    --domain example.com \
    --protocol mcp \
    --endpoint agent.example.com \
    --capability chat \
    --capability code-review

# Publish with transport and auth metadata (v0.10.0+)
dns-aid publish \
    --name billing \
    --domain example.com \
    --protocol mcp \
    --endpoint mcp.example.com \
    --capability billing --capability invoicing \
    --transport streamable-http \
    --auth-type bearer

# Publish with DNS-AID custom SVCB parameters (v0.4.8+)
dns-aid publish \
    --name booking \
    --domain example.com \
    --protocol mcp \
    --endpoint mcp.example.com \
    --capability travel --capability booking \
    --cap-uri https://mcp.example.com/.well-known/agent-cap.json \
    --cap-sha256 dGVzdGhhc2g \
    --bap "mcp/1,a2a/1" \
    --policy-uri https://example.com/agent-policy \
    --realm production

# Discover agents at a domain (pure DNS - default)
dns-aid discover example.com

# Discover with substrate filters
dns-aid discover example.com --protocol mcp --name chat

# Discover with in-memory filters (v0.19.0+)
dns-aid discover example.com \
    --capabilities payment-processing --capabilities fraud-detection \
    --auth-type oauth2 --realm prod \
    --require-signed --require-signature-algorithm ES256

# Cross-domain search via a directory the caller has chosen (v0.19.0+)
export DNS_AID_SDK_DIRECTORY_API_URL=https://your-directory.example.com
dns-aid search "payment processing" --protocol mcp

# Discover via HTTP index (richer metadata; format aligns with the ANS schema)
dns-aid discover example.com --use-http-index

# Output as JSON
dns-aid discover example.com --json

# Verify DNS records
dns-aid verify my-agent.example.com

# List DNS-AID records in a zone
dns-aid list example.com

# List available zones (Route 53)
dns-aid zones

# Delete an agent
dns-aid delete --name my-agent --domain example.com --protocol mcp

# Index Management (v0.3.0+)
# List agents in a domain's index record
dns-aid index list example.com

# Sync index with actual DNS records (useful for repair)
dns-aid index sync example.com

# Advertise an ARD ai-catalog via DNS pointer (host-anywhere; v0.26.0+)
# Publishes _catalog._agents + _index._agents SVCB → the catalog host.
dns-aid index publish-catalog example.com catalogue.example.com

# Publish without updating the index (for internal agents)
dns-aid publish --name internal-bot --domain example.com --protocol mcp --no-update-index

# Domain Submission to a Directory (v0.4.0+)
# Submit your domain to a directory of your choice for indexing.
# The --to flag (or DNS_AID_SDK_DIRECTORY_API_URL) selects which directory.
dns-aid submit example.com --to https://your-directory.example.com

# Submit with company metadata
dns-aid submit example.com \
    --to https://your-directory.example.com \
    --company-name "Example Corp" \
    --company-website "https://example.com" \
    --company-description "We build AI agents"

Agent Index Records

DNS-AID v0.3.0 automatically maintains an index record at _index._agents.{domain} for efficient discovery:

_index._agents.example.com. TXT "agents=chat:mcp,billing:a2a,support:https"

Benefits:

• Single DNS query discovers all agents at a domain
• Crawlers can efficiently index domains
• Explicit list of published agents (no guessing)

The index is updated automatically when you publish or delete agents. Use --no-update-index to opt out for internal agents.

Domain Control Validation (v0.20.0+)

DCV lets one party prove to another that they control a DNS zone, using a short-lived TXT record challenge. Two use cases: anonymous agents asserting org affiliation, and directory anti-impersonation before listing an agent as org-verified.

# Challenger: issue a challenge for a domain
CHALLENGE=$(dns-aid dcv issue orgb.example.com --agent assistant --issuer orga.example.com --json)
TOKEN=$(echo $CHALLENGE | python3 -c "import sys,json; print(json.load(sys.stdin)['token'])")

# Claimant: place the challenge TXT record in the zone (using their own DNS credentials)
dns-aid dcv place orgb.example.com $TOKEN

# Challenger: verify the record is present and unexpired
dns-aid dcv verify orgb.example.com $TOKEN

# Claimant: revoke after successful verification
dns-aid dcv revoke orgb.example.com $TOKEN

from dns_aid.core import dcv

# Challenger
challenge = dcv.issue("orgb.example.com", agent_name="assistant", issuer_domain="orga.example.com")
# ... deliver challenge out-of-band to claimant ...

# Claimant (different process, different credentials)
await dcv.place(challenge.domain, challenge.token, bnd_req=challenge.bnd_req)

# Challenger
result = await dcv.verify(challenge.domain, challenge.token, expected_bnd_req=challenge.bnd_req)
if result.verified:
    await dcv.revoke(challenge.domain, token=challenge.token)

See Domain Control Validation in the API reference for full details.

HTTP Index Discovery

DNS-AID also supports HTTP-based agent discovery, with an index format whose schema aligns with ANS-style directories. This provides richer metadata (descriptions, model cards, capabilities, costs) while still validating endpoints via DNS.

Endpoint patterns tried (in order):

1. https://index.aiagents.{domain}/index-wellknown (demo-friendly, no underscores)
2. https://_index._aiagents.{domain}/index-wellknown (ANS-style)
3. https://{domain}/.well-known/agents-index.json (well-known path)

Capability Document endpoint (v0.4.8+):

• https://index.aiagents.{domain}/cap/{agent-name} — returns a capability document JSON per agent

# Fetch HTTP index directly
curl https://index.aiagents.example.com/index-wellknown

# Fetch capability document for a specific agent
curl https://index.aiagents.example.com/cap/booking-agent

# CLI with HTTP index
dns-aid discover example.com --use-http-index

# Python with HTTP index
agents = await dns_aid.discover("example.com", use_http_index=True)

Discovery Method	When to Use
DNS (default)	Maximum decentralization, offline caching, minimal round trips
HTTP Index	Rich metadata upfront, ANS compatibility, model cards, capabilities, direct endpoints

FQDN as Source of Truth (v0.4.7): The HTTP index only needs to provide each agent's FQDN (e.g., booking.example.com). Agent name and protocol are extracted from the FQDN — no separate protocols field needed. DNS SVCB lookup then resolves the authoritative endpoint.

Discovery Transparency (v0.4.6+): Each discovered agent includes source fields showing how data was resolved:

Field	Values	Description
endpoint_source	dns_svcb, http_index_fallback, direct	How the endpoint was resolved
capability_source	cap_uri, txt_fallback, none	How capabilities were discovered (v0.4.8+)

Capability Resolution (v0.4.8+): Capabilities are resolved with the following priority:

1. SVCB cap URI → fetch capability document (JSON with capabilities, version, description)
2. TXT record fallback → capabilities=chat,support from DNS TXT record
3. HTTP Index inline → capabilities embedded in the index JSON response

MCP Server

DNS-AID includes an MCP (Model Context Protocol) server that allows AI agents like Claude to publish and discover other agents.

Running the MCP Server

# Run with stdio transport (default - for Claude Desktop, etc.)
dns-aid-mcp

# Run with HTTP transport
dns-aid-mcp --transport http --port 8000

Available MCP Tools

Tool	Description
publish_agent_to_dns	Publish an AI agent to DNS (auto-updates index)
discover_agents_via_dns	Discover AI agents at a domain (supports use_http_index for HTTP-index discovery)
list_agent_tools	List available tools on a discovered MCP agent
call_agent_tool	Call a tool on a discovered MCP agent (proxy requests)
verify_agent_dns	Verify DNS-AID records and security
list_published_agents	List all agents in a domain
delete_agent_from_dns	Remove an agent from DNS (auto-updates index)
list_agent_index	List agents in domain's index record
sync_agent_index	Sync index with actual DNS records
diagnose_environment	Run environment diagnostics (deps, DNS, backends)

Claude Desktop Integration

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "dns-aid": {
      "command": "dns-aid-mcp"
    }
  }
}

Then Claude can discover and connect to AI agents:

"Find available agents at example.com"

"Publish my chat agent to DNS at mycompany.com"

"Discover agents at example.com and search for flights from SFO to JFK"

Live Demo

Try the live demo with Claude Desktop:

{
  "mcpServers": {
    "dns-aid": {
      "command": "python",
      "args": ["-m", "dns_aid.mcp.server"]
    }
  }
}

Then ask Claude to discover and use the booking agent:

"Discover agents at example.com using HTTP index, find a booking agent, and search for flights from SFO to JFK on March 15th 2026"

Claude will:

1. Call discover_agents_via_dns → finds booking-agent at https://booking.example.com/mcp
2. Call list_agent_tools → sees search_flights, get_flight_details, check_availability, create_reservation
3. Call call_agent_tool → searches for flights and returns results

How It Works

DNS-AID uses SVCB records (RFC 9460) to advertise AI agents:

chat.example.com. 3600 IN SVCB 1 chat.example.com. alpn="a2a" port=443 mandatory="alpn,port"
chat.example.com. 3600 IN TXT "capabilities=chat,assistant" "version=1.0.0"

DNS-AID Custom SVCB Parameters (v0.4.8+): Per the IETF draft, SVCB records can carry additional custom parameters for richer agent metadata:

booking.example.com. SVCB 1 mcp.example.com. alpn="mcp" port=443 \
    cap="https://mcp.example.com/.well-known/agent-cap.json" \
    cap-sha256="dGVzdGhhc2g" bap="mcp/1,a2a/1" \
    policy="https://example.com/agent-policy" realm="production"

Parameter	Purpose
cap	URI to capability document (rich JSON metadata)
cap-sha256	SHA-256 digest of capability descriptor for integrity verification
bap	Supported bulk agent protocols with versioning
policy	URI to agent policy document
realm	Multi-tenant scope identifier

This allows any DNS client to discover agents without proprietary protocols or central registries.

Discovery Flow (DNS-AID Draft Aligned)