feat(storage): tinystoragedrivers adapters for the harness store and graph checkpointer

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "vendor/tinyliveagents"]
 	path = vendor/tinyliveagents
 	url = https://github.com/tinyhumansai/tinyliveagents.git
+[submodule "vendor/tinystoragedrivers"]
+	path = vendor/tinystoragedrivers
+	url = https://github.com/tinyhumansai/tinystoragedrivers.git

AGENTS.md

@@ -21,8 +21,10 @@ dedicated `types.rs` file and keep module-local unit tests in a sibling
 smallest useful API.
 
 Cargo features are package-local. `tinyagents-harness` exposes `sqlite`,
-`tools`, `multimodal`, and `tracing`; `tinyagents-graph` exposes `sqlite` and
-`tracing`; registry and session expose `tracing`. Tracing instrumentation is
+`tools`, `multimodal`, `storage-drivers`, and `tracing`; `tinyagents-graph`
+exposes `sqlite`, `storage-drivers`, and `tracing`; session exposes
+`storage-drivers` and `tracing`; registry exposes `tracing`. The
+`storage-drivers` features put each store on `tinystoragedrivers` ports. Tracing instrumentation is
 compiled out by default.
 
 Integration tests are in `crates/tinyagents-integration-tests/tests/`, covering serialization, graph routing,

Cargo.toml

@@ -31,6 +31,9 @@ serde_json = "1"
 tempfile = "3"
 tokio = { version = "1", default-features = false, features = ["macros", "rt-multi-thread"] }
 tracing = "0.1"
+# Storage ports from the vendored tinystoragedrivers submodule. Hosts that
+# vendor tinyagents use this same copy, so there is one set of port types.
+tinystoragedrivers-core = { path = "vendor/tinystoragedrivers/crates/tinystoragedrivers-core", version = "0.3.0" }
 uuid = { version = "1", features = ["v4"] }
 
 [workspace.lints.rust]
@@ -52,3 +55,4 @@ strip = "debuginfo"
 [patch."https://github.com/tinyhumansai/tinytools"]
 tinytools-agent = { path = "vendor/tinytools/crates/tinytools-agent" }
 tinytools = { path = "vendor/tinytools/crates/tinytools" }
+

crates/tinyagents-graph/Cargo.toml

@@ -22,10 +22,17 @@ tinyinference-llm = { path = "../../vendor/tinyinference/crates/tinyinference-ll
 tinytools = { path = "../../vendor/tinytools/crates/tinytools", version = "0.5.0" }
 tokio = { workspace = true, features = ["sync", "time", "macros", "rt", "rt-multi-thread", "fs"] }
 tracing = { workspace = true }
+# Storage ports (no database client) for `DriverCheckpointer`.
+tinystoragedrivers-core = { workspace = true, optional = true }
+# Collision-resistant ids for `DriverCheckpointer` keys too long to store.
+sha2 = { version = "0.11", optional = true }
 
 [features]
 default = []
 sqlite = ["dep:rusqlite"]
+# `DriverCheckpointer`: checkpoints, pending writes and leases on any
+# tinystoragedrivers backend the host opened.
+storage-drivers = ["dep:tinystoragedrivers-core", "dep:sha2"]
 # Tracing instrumentation is now always compiled in (via the `tracing` crate
 # dependency above). This feature is retained as a no-op so downstream
 # feature forwards keep compiling.

crates/tinyagents-graph/src/checkpoint/README.md

@@ -93,3 +93,25 @@ crashes mid-execution.
 - `DurabilityMode` trades persistence frequency for write volume — a mode that
   only checkpoints on interrupt/failure means a mid-run crash loses all
   progress since the last such boundary, not just the current node.
+
+## `DriverCheckpointer` (`storage-drivers` feature)
+
+`DriverCheckpointer` stores checkpoints, pending writes and execution leases in
+a [tinystoragedrivers](https://github.com/tinyhumansai/tinystoragedrivers)
+`DocumentStore`. Hosts use it to put graph durability on whichever backend they
+opened, such as SQLite or MongoDB. The handle is bound to a tenant scope, so
+tenants that share a thread id still never see each other's checkpoints.
+
+It uses four collections, all prefixed `graph` by default:
+
+- `<prefix>_checkpoints`: one document per stored checkpoint, keyed by a
+  per-thread insertion sequence. Duplicate ids resolve to the latest write,
+  as in the append-only backends.
+- `<prefix>_threads`: the per-thread sequence counter, advanced with
+  compare-and-swap.
+- `<prefix>_writes`: merged pending writes per `(thread, namespace, checkpoint)`.
+- `<prefix>_leases`: per-thread execution leases, claimed, renewed and
+  released with compare-and-swap.
+
+It passes the same `testkit::conformance` contracts as the bundled backends:
+checkpointer, writes, lineage and concurrency.