docs: add complete escrow entrypoint and error-code reference

README.md

@@ -84,6 +84,7 @@ agentpay-contracts/
 ## Documentation
 
 - [Escrow: Build, Test, and Deploy Guide](docs/escrow/build-deploy.md) — build the release WASM, run the test suite, and deploy to testnet with the Stellar/Soroban CLI.
+- [Escrow: Entrypoint & Error-Code Reference](docs/escrow/api.md) — every entrypoint with its signature, auth/pause requirements, and panics, plus the full `EscrowError` catalogue.
 
 ## CI/CD
 

docs/escrow/api.md

@@ -0,0 +1,74 @@
+# Escrow — Entrypoint & Error-Code Reference
+
+Authoritative reference for the AgentPay escrow contract
+(`contracts/escrow/src/lib.rs`). Cross-checked against the source. Error
+codes are **append-only** — never reuse or renumber a variant.
+
+`require_auth` column: principal whose signature is required. "Pause"
+column: whether the entrypoint panics with `ContractPaused` (#4) while the
+contract is paused.
+
+## Write entrypoints
+
+| Entrypoint | Params | Auth | Pause | Returns | Panics |
+|---|---|---|---|---|---|
+| `init` | `admin: Address` | `admin` (once) | no | — | #1 AlreadyInitialized |
+| `record_usage` | `agent, service_id, requests: u32` | none | yes | `UsageRecord` (new total) | #2, #4, #7, #8, #9, #10, #12 |
+| `settle` | `agent, service_id` | admin | yes | `i128` billed | #3, #4 |
+| `set_service_price` | `service_id, price_stroops: i128` | admin | no | — | #2 (negative price), #3 |
+| `register_service` | `service_id` | admin | no | — | #3 |
+| `unregister_service` | `service_id` | admin | no | — | #3 |
+| `set_service_disabled` | `service_id, disabled: bool` | admin | no | — | #3 |
+| `set_service_metadata` | `service_id, description, owner` | admin | no | — | #3 |
+| `clear_service_metadata` | `service_id` | admin | no | — | #3 |
+| `transfer_service_ownership` | `caller, service_id, new_owner` | owner or admin | yes | — | #3, #4, #6 (unauthorized), #13 |
+| `set_agent_allowed` | `agent, allowed: bool` | admin | no | — | #3 |
+| `set_allowlist_enabled` | `enabled: bool` | admin | no | — | #3 |
+| `set_min_requests_per_call` | `min_requests: u32` | admin | no | — | #3 |
+| `set_max_requests_per_call` | `max_requests: u32` | admin | no | — | #3 |
+| `set_require_service_registration` | `required: bool` | admin | no | — | #3 |
+| `pause` | — | admin | n/a | — | #3 |
+| `unpause` | — | admin | n/a | — | #3 |
+| `propose_admin_transfer` | `new_admin` | admin | no | — | #3, #14 (self-target) |
+| `cancel_admin_transfer` | — | admin | no | — | #3 |
+| `accept_admin_transfer` | `caller` | pending admin | no | — | #5, #6 |
+| `migrate_v1_to_v2` | — | admin | no | — | #3, #11 |
+
+## Read entrypoints (no auth, no pause)
+
+`get_admin`, `get_pending_admin`, `get_usage`, `get_service_price`,
+`compute_billing`, `get_last_settlement`, `get_total_requests_all_time`,
+`get_total_usage_by_agent`, `get_min_requests_per_call`,
+`get_max_requests_per_call`, `is_allowlist_enabled`, `is_agent_allowed`,
+`is_service_registration_required`, `is_service_registered`,
+`is_service_disabled`, `is_paused`, `get_service_metadata`,
+`get_schema_version`, `version`.
+
+`compute_billing` saturates at `i128::MAX`; `get_schema_version` defaults
+to 1 when absent; counters default to 0; flags default to `false`.
+
+## Error-code catalogue (`EscrowError`)
+
+| Code | Variant | Trigger | Raised by |
+|---|---|---|---|
+| 1 | AlreadyInitialized | admin already set | `init` |
+| 2 | RequestsMustBePositive | `requests == 0` (also reused for negative price) | `record_usage`, `set_service_price` |
+| 3 | NotInitialized | admin-gated call before `init` | all admin entrypoints |
+| 4 | ContractPaused | called while paused | `record_usage`, `settle`, `transfer_service_ownership` |
+| 5 | NoPendingAdminTransfer | accept with nothing pending | `accept_admin_transfer` |
+| 6 | NotPendingAdmin | accept by wrong address (also reused for unauthorized ownership transfer) | `accept_admin_transfer`, `transfer_service_ownership` |
+| 7 | ServiceNotRegistered | strict mode + unknown service | `record_usage` |
+| 8 | RequestsExceedsMaxPerCall | `requests > MaxRequestsPerCall` | `record_usage` |
+| 9 | RequestsBelowMinPerCall | `requests < MinRequestsPerCall` | `record_usage` |
+| 10 | AgentNotAllowed | allowlist on + agent not allowed | `record_usage` |
+| 11 | MigrationVersionMismatch | migrate from non-v1 schema | `migrate_v1_to_v2` |
+| 12 | ServiceDisabled | service disabled | `record_usage` |
+| 13 | ServiceMetadataNotFound | metadata-scoped call with no metadata | `transfer_service_ownership` |
+| 14 | InvalidAdminProposal | propose current admin as new admin | `propose_admin_transfer` |
+
+## Versioning
+
+- `version()` returns the compiled contract version (currently `2`).
+- `get_schema_version()` returns the persisted storage-layout version.
+
+See [migrations.md](migrations.md) for the migration workflow.