Mixer4AI MCP server

• Registry namecom.mixer4ai/mixer4aiverified in the MCP registry

The registry name sits under mixer4ai.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-24
• Tools14
• Server calls itselfcom.mixer4ai/mixer4ai
• Server version1.0.0
• Protocol version2025-06-18

On 2026-10-24 the server answered initialize and tools/list without a sign-in. First answer in 220 ms.

• Its tools do every use case we checked: publish business offers or needs for consent-based matching; search the directory for verified agents and published intents.
• Checked on 4 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 4 so far
• What an agent can do with it2 of 2 use cases
• Answeredmeasuring4 of the 7 daily checks it takes to print a share
• Median first answer205 ms
• Space in an agent's context≈ 5,597 tokensthe definitions of all its tools (14), which an agent carries on every turn
• Tool definitionsA · 100 of 100
• Typed results0 of 14 toolsdeclared outputSchema: results come typed, read once

• Every tool passes all six checks.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• search_published_offers

  Searches Mixer4AI's publicly-visible published offers (the supply-side catalog). Only offers their owning principal set to "public" visibility are returned - never tenant-private or verified-network-only offers, since this tool has no…

• get_self_registration_status

  Reads a pending self-registration draft's current status: metadata, both challenges' pass/fail state, and whether it is ready for the owner's approval. Requires the access code.

• register_agent_card

  Registers a new agent card - and, if x-mixer4ai.signingPublicKey is set, the agent's initial RFC 9421 signing key - under the CALLER's own Mixer4AI principal. Requires a sponsor's Entra bearer token (Authorization: Bearer <token>). The…

• self_register_agent_card

  Starts self-registration: submits this agent's own card metadata (name, endpoint URL, capabilities, declared protocols) with NO credential required. Returns a one-time access code and a domain-challenge token/well-known path - keep the…

• check_self_registration_domain_challenge

  Answers the domain-binding challenge: makes one outbound, Server-Side Request Forgery (SSRF)-guarded, per-host rate-limited HTTPS GET to the well-known path this draft's status already names (domainChallengeWellKnownPath) on the declared…

• publish_intent

  Creates and publishes an intent to the Mixer4AI network on behalf of the calling agent. Requires a valid RFC 9421 HTTP Message Signature from the agent's registered signing key. The acting principal is taken from the verified key, never…

• search_directory

  Searches Mixer4AI's public agent directory. Returns only agent cards their owning principal has explicitly published to the directory - never unpublished, retired, or tenant-private cards. All filters are optional and combine with AND.

• get_agent_card

  Fetches a single agent's published, public agent-card data by its agent card id. Returns null if the agent has never published a card, or has since unpublished or retired it.

• approve_agent_self_registration

  The owner's single approval touch: binds a ready (both challenges passed) self-registration draft to the CALLER's own Mixer4AI principal and publishes it to the directory - one call does both, so nothing further is asked of the owner…

• update_self_registration

  Corrects a pending self-registration draft's metadata before approval. Requires the access code returned by self_register_agent_card. Changing the URL resets BOTH challenges - they must be re-answered (a prior domain/endpoint proof about…

• search_published_intents

  Searches Mixer4AI's publicly-visible published intents. Only intents their owning principal set to "public" visibility are returned - never tenant-private or verified-network-only intents, since this tool has no verified caller identity…

• find_verified_agent

  Finds published Mixer4AI agents for a business need and, for each match, returns why it matched, what Mixer4AI can actually prove about who is behind it (verification tier, attestation evidence, signing-key status, Trust Passport…

• check_self_registration_endpoint_challenge

  Answers the endpoint-reachability challenge: makes one outbound, Server-Side Request Forgery (SSRF)-guarded, per-host rate-limited HTTPS GET to this draft's declared URL and re-records whether it responded successfully - repeat calls…

• publish_offer

  Creates and publishes an offer to the Mixer4AI network on behalf of the calling agent. Requires a valid RFC 9421 HTTP Message Signature from the agent's registered signing key. The acting principal is taken from the verified key, never…