Attach a Project mount to a Session

Attaches a Project mount declaration to the Session: project_id, an absolute mount_path that may not overlap another mount, access, and a revision_policy of latest or a pinned revision. Declarations may only change at a turn boundary — while the Session holds no active turn — and are refused as an invalid transition otherwise. A latest policy re-resolves to an immutable revision at the start of every Run, and each resolution is recorded in that Run’s session.mounts_resolved. For a Git Project, mounting is also an instruction trust action: a read-enabled Agent receives an index of D54-valid Skills found exactly at .claude/skills/<name>/SKILL.md in that frozen revision; nested or package-local entries are not announced, and no catalog Skill is created. Accepts an Idempotency-Key and returns the appended event envelope with 201.

Checkfu support posture: alpha; hosted. Required evidence journey: session-turn. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities.

POST /v1/sessions/{id}/mounts

Attach a Project mount to a Session

cURL

curl --request POST \
  --url https://api.checkfu.com/v1/sessions/{id}/mounts \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'checkfu-version: <checkfu-version>' \
  --data '
{
  "kind": "project",
  "project_id": "<string>",
  "mount_path": "<string>",
  "revision_policy": {
    "kind": "latest"
  },
  "writeback": null
}
'

201

{
  "id": "<string>",
  "seq": 1,
  "schema_version": 1,
  "created_at": "<string>",
  "type": "user.message",
  "payload": {
    "content": "<string>",
    "authored_by": "<string>",
    "caused_by": {
      "kind": "api",
      "request_id": "<string>"
    },
    "attachments": [
      "<string>"
    ],
    "prompt_integrity": {
      "analyzer_version": "unicode-17.0.0-uts39-r32-checkfu-1",
      "disposition": "accepted_normalization",
      "original_digest": "<string>",
      "findings": [
        {
          "kind": "mixed_script_confusable",
          "utf16_offset": 1,
          "code_point": "<string>",
          "replacement": "<string>",
          "answer_id": "<string>",
          "value_index": 1
        }
      ]
    },
    "connected_runtime": "<string>",
    "run_delivery": "next_run",
    "host_context": {
      "source": "<string>",
      "data": {}
    },
    "surface_scope_id": "<string>"
  },
  "attested": true
}

Authorizations

Authorization · string · header · required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Headers

checkfu-version · enum<string> · required

Available options: 2026-08-24

idempotency-key · string

Maximum string length: 255

Path Parameters

id · string · required

Pattern: ^sess_[0-9a-f]{32}$

Body

application/json

Option 1

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kind · enum<string> · required

Available options: project

project_id · string · required

Pattern: ^prj_[0-9a-f]{32}$

mount_path · string · required

Required string length: 2 - 1024

revision_policy · object · required

Option 1

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Show child attributes

access · enum<string> · required

Available options: read_only, read_write

writeback · null

Response

201

application/json

Success

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id · string · required

Pattern: ^evt_[0-9a-f]{32}$

seq · integer · required

Required range: x > 0

schema_version · enum<number> · required

Available options: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42

created_at · string · required

type · enum<string> · required

Available options: user.message

payload · object · required

Show child attributes

attested · enum<boolean>

Available options: true