Buying from a
live seller agent.

02 Three things that will trip you up

Read these before you write any code. Each one costs an hour if you find it the hard way.

04 Targeting: synaptic audiences

This is the part that isn’t a cookie. A synaptic audience is a session-scoped, cookieless audience derived from the connections a reader traverses — the meaning of the current page plus the trajectory of pages before it — rather than from any persistent identifier.

There is no profile, no ID graph, and nothing to sync. The segment is computed from where the reader is and where they just came from, and it evaporates when the session does. Generation is deterministic keyword rules over essay frontmatter, not runtime inference, so the same reader path always produces the same segment — and the rules are readable in the repo.

Pick one route — they escalate

There are five ways to say who you want, and you only need one. They are ordered by how much you have to know up front. Start at A. Go down a rung only when the rung above can’t express what you mean — every step down buys precision with a bit more machinery, and D and E are the only ones that touch a second system.

1. A

   Buy the product as-is

   You want reach across the whole essay set and the product’s own definition is already the audience.

   Omit targeting from the package. Nothing else to learn.

2. B

   Name the pages — essay_slugs

   You have read the site and know exactly which essays you want to sit beside.

   Put slugs on the package. Deterministic, no matching involved.

3. C

   Name the audience — segment_ids

   You want the reader regardless of which essay they landed on, and one of the 20 segments below already says it.

   Put segment ids on the package. Browse them in /synaptic/catalog.

4. D

   Describe it — brief

   You can say it in a sentence but don’t want to read a segment list first. This is the common case.

   Send prose to get_products; a product is composed for you (section 05).

5. E

   Use your own vocabulary — concept_bridge

   You already work in UCP concept ids across several publishers and want to address this inventory in the nouns you hold, not ours.

   Add concept_bridge: true to the same brief call. Detailed below.

A, B and C are the seller agent alone. D adds in-house brief matching. E is the only route that calls a second agent — and if that agent is down, E degrades to D rather than failing.

Where B and C go in the request

Targeting lives on the package, not the buy. Two dimensions, and they are ORed — a slot matches if it satisfies either one. Omit targeting entirely and you are on route A.

"targeting": {
  "segment_ids": ["syn_agentic_standards", "syn_agent_governance"],
  "essay_slugs": ["adcp-vs-aamp", "the-answerer-of-record"]
}

The catalog (route C)

Twenty segments, each listing every member essay so you can audit exactly what you are buying. Measured serve beacons replace the estimates as they accumulate.

curl -s https://sell.nofluffadvisory.com/synaptic/catalog

Invoke-RestMethod -Uri 'https://sell.nofluffadvisory.com/synaptic/catalog' | ConvertTo-Json -Depth 10

{
  "catalog_version": "…",
  "definition": "A synaptic audience is a session-scoped, cookieless audience derived from the connections a reader traverses — the meaning of the current page plus the trajectory of pages before it — rather than from any persistent identifier.",
  "generation": "Deterministic keyword rules over essay frontmatter (scripts/generate-synaptic-facets.mjs, reviewable in the repo). No runtime inference.",
  "segments": [
    {
      "segment_id": "syn_agentic_standards",
      "name": "Agentic standards evaluators",
      "audience": "Practitioners tracking AdCP/AAMP/UCP and the agentic protocol layer.",
      "member_slugs": ["adcp-the-open-standard-for-agentic-advertising",
                       "adcp-vs-aamp", "…"]
    }
    … 19 more segments
  ]
}

Route E in full: where the signals agent fits

There is a second agent at adcp.signal-stack.io speaking AdCP’s signals protocol, and it is independently operated — separate codebase, separate deploy, separate uptime. By default this seller agent does not call it, and discovery never depends on it.

What the two now share is a vocabulary, not a retrieval path. Synaptic ids like syn_clean_rooms are publisher-local — useful here, meaningless to anyone else. UCP concept ids like CLEAN_ROOM_PRACTITIONER live in a shared registry, so two publishers can be compared on the same noun. Each segment now publishes its concept ids in /synaptic/catalog, computed at build time.

Be clear what that buys you: comparability, not accuracy. Brief matching here is already good without it. What it adds is the ability to address this inventory in nouns you already hold.

The concept ids also resolve the other way. On the signals agent, a concept can carry member_nodes pointing at its own catalog — so CDP_ARCHITECT hands back sig_bi_data_platform_eval alongside our syn_cdp_architecture. One noun, two independently operated inventories. That crosswalk covers 4 of the 16 B2B concepts today; the rest carry no nodes, for the same reason the segments above carry no concepts.

Making the route E call

Pass concept_bridge: true to get_products and your brief is resolved against the UCP registry as well as in-house, then mapped back to inventory. It only ever widens the result, so opting in cannot make the answer worse.

curl -s -X POST https://sell.nofluffadvisory.com/mcp \
  -H 'content-type: application/json' \
  -d '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_products",
    "arguments": {
      "brief": "identity resolution and addressability after third party cookies",
      "concept_bridge": true
    }
  }
}'

$body = @'
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_products",
    "arguments": {
      "brief": "identity resolution and addressability after third party cookies",
      "concept_bridge": true
    }
  }
}
'@

$r = Invoke-RestMethod -Uri 'https://sell.nofluffadvisory.com/mcp' -Method Post `
  -ContentType 'application/json' `
  -Body $body

$r.result.content[0].text

{
  "adcp_version": "3.1",
  "status": "completed",
  "products": [
    {
      "product_id": "prod_dyn_identity_84fllj",
      "segment_ids": ["syn_identity", "syn_clean_rooms", "syn_first_party_data"],
      "curation": {
        "resolution": "concept_v1",
        "concept_bridge": {
          "fired": true,
          "agent": "adcp.signal-stack.io",
          "concepts": ["IDENTITY_RESOLUTION_STRATEGIST"],
          "note": "UCP concept ids resolved to inventory via the build-time segment mapping."
        }
      }
    }
    … the four static products follow, unchanged
  ],
  "curation": "dynamic_hybrid_v1"
}

The response always states whether the bridge actually contributed. resolution only reads concept_v1 when a bridged segment made the final cut; otherwise you get hybrid_v1 and a concept_bridge.reason — not_requested, no_dominant_concept, concepts_unmapped_to_inventory, signals_unreachable. Same rule as everything else here: a signal that didn’t contribute is never dressed up as one that did. The call has a 3s timeout and degrades to the normal path, so the second agent can be down without breaking your buy.

06 Creating the media buy

The first call that needs a bearer. Required fields are brand, packages and budget; everything else is optional but most of it is worth sending.

curl -s -X POST https://sell.nofluffadvisory.com/mcp \
  -H 'content-type: application/json' \
  -H 'authorization: Bearer demo-yourname' \
  -d '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create_media_buy",
    "arguments": {
      "buyer_ref": "my-first-adcp-buy",
      "buyer_agent": "https://your-agent.com",
      "brand": {
        "name": "Your Brand",
        "domain": "yourbrand.com"
      },
      "packages": [
        {
          "product_id": "prod_interop_test",
          "buyer_ref": "pkg-1",
          "targeting": {
            "segment_ids": [
              "syn_agentic_standards"
            ]
          }
        }
      ],
      "budget": 1,
      "currency": "USD",
      "idempotency_key": "my-first-buy-001"
    }
  }
}'

$body = @'
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create_media_buy",
    "arguments": {
      "buyer_ref": "my-first-adcp-buy",
      "buyer_agent": "https://your-agent.com",
      "brand": {
        "name": "Your Brand",
        "domain": "yourbrand.com"
      },
      "packages": [
        {
          "product_id": "prod_interop_test",
          "buyer_ref": "pkg-1",
          "targeting": {
            "segment_ids": [
              "syn_agentic_standards"
            ]
          }
        }
      ],
      "budget": 1,
      "currency": "USD",
      "idempotency_key": "my-first-buy-001"
    }
  }
}
'@

$r = Invoke-RestMethod -Uri 'https://sell.nofluffadvisory.com/mcp' -Method Post `
  -ContentType 'application/json' `
  -Headers @{ Authorization = 'Bearer demo-yourname' } `
  -Body $body

$r.result.content[0].text

What comes back

{
  "adcp_version": "3.1",
  "status": "completed",
  "media_buy_id": "mb_dc593a7ea963",
  "buyer_ref": "my-first-adcp-buy",
  "media_buy_status": "pending_creatives",
  "budget": 1, "currency": "USD", "cpm": 1,
  "packages": [
    { "package_id": "pk_9f2c1a44b8e0", "product_id": "prod_interop_test" }
  ],
  "governance": {
    "machine_gate": "pass",
    "policy_flags": [],
    "human_review": { "status": "pending", "floor_usd": 0 }
  }
}

Note the two different status fields. The envelope status is the task — your call succeeded. The media_buy_status is the buy — it is waiting on creatives and a human. Domain state never rides the envelope slot.

Fields worth knowing

curl -s -X POST https://sell.nofluffadvisory.com/mcp \
  -H 'content-type: application/json' \
  -H 'authorization: Bearer demo-yourname' \
  -d '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_media_buys",
    "arguments": {
      "buyer_ref": "my-first-adcp-buy"
    }
  }
}'

$body = @'
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_media_buys",
    "arguments": {
      "buyer_ref": "my-first-adcp-buy"
    }
  }
}
'@

$r = Invoke-RestMethod -Uri 'https://sell.nofluffadvisory.com/mcp' -Method Post `
  -ContentType 'application/json' `
  -Headers @{ Authorization = 'Bearer demo-yourname' } `
  -Body $body

$r.result.content[0].text

{
  "adcp_version": "3.1",
  "status": "completed",
  "media_buys": [
    {
      "media_buy_id": "mb_15cf038726e0",
      "buyer_ref": "my-first-adcp-buy",
      "media_buy_status": "pending_creatives",
      "budget": 1, "currency": "USD", "cpm": 1,
      "sandbox": true,
      "packages": [
        {
          "package_id": "pk_f3159f795e41",
          "product_id": "prod_interop_test",
          "buyer_ref": "pkg-1",
          "pricing_option_id": "cpm_usd_fixed",
          "targeting": { "segment_ids": ["syn_agentic_standards"] }
        }
      ],
      "governance": {
        "machine_gate": "pass",
        "policy_flags": [],
        "human_review": { "status": "pending", "floor_usd": 0 }
      },
      "valid_actions": ["pause", "cancel"]
    }
  ]
}