Move `ldk-server-mcp` into the workspace by tnull · Pull Request #188 · lightningdevkit/ldk-server

tnull · 2026-04-15T09:37:11Z

Moving from https://github.com/tnull/ldk-server-mcp

Draft for now.

ldk-reviews-bot · 2026-04-15T09:37:14Z

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benthecarman

Did a quick skim and ran through codex

Codex Review:

  - [P2] Honor storage.disk.dir_path when resolving credentials — /home/ben/projects/ldk-server/ldk-server-mcp/src/
    config.rs:57-60
    If the shared ldk-server config uses a custom storage.disk.dir_path, this parser drops that section entirely, so
    resolve_config() can only look in ~/.ldk-server/... for api_key and tls.crt. In deployments that store node state
    outside the default directory (a setup ldk-server-cli already supports), the MCP bridge will fail to authenticate
    unless users also set both LDK_API_KEY and LDK_TLS_CERT_PATH by hand.
  - [P2] Fall back to the default gRPC address when no base URL is configured — /home/ben/projects/ldk-server/ldk-
    server-mcp/src/config.rs:112-116
    In setups that rely on the standard 127.0.0.1:3536 gRPC address and only use the default credential files on disk,
    this path exits with “Base URL not provided” instead of using the same default as ldk-server-cli. As a result, ldk-
    server-mcp cannot start in the zero-config case unless users create a config file or export LDK_BASE_URL, even
    though the server is running at the normal address.

I think these are two things we fixed in the cli since you created the MCP server.

benthecarman

needs rebase too

benthecarman · 2026-04-26T22:46:34Z

+// string, so we manually extract the string and turn it into bytes instead of delegating to the
+// proto-typed deserializer.
+pub async fn handle_sign_message(client: &LdkServerClient, args: Value) -> Result<Value, McpError> {
+	let message = args


any reason we aren't using the json decoder here? and in handle_verify_signature

Hmm, see the comment above. Now introduced some extra {SignMessage,VerifySignature}Args structs deriving Deserialize to make this a bit cleaner. Let me know what you think.

benthecarman · 2026-04-26T22:49:30Z

+- **Spec**: https://spec.modelcontextprotocol.io/
+- **Transport**: stdio (one JSON-RPC 2.0 message per line)
+- **Methods implemented**: `initialize`, `tools/list`, `tools/call`
+- **Notifications handled**: `notifications/initialized` (ignored, no response)


I don't see us handling this anywhere, looks like we'd return METHOD_NOT_FOUND

No, we just skip in main:

// Notifications have no id — do not respond if request.id.is_none() { continue; }

+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@nightly


+      - name: Get the current date
+        run: echo "date=$(date +'%Y-%m-%d')" >> $GITHUB_ENV
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v8


+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@nightly


+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@nightly


+      - name: Get the current date
+        run: echo "date=$(date +'%Y-%m-%d')" >> $GITHUB_ENV
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v8


Derive `serde::Deserialize` (alongside the existing `serde::Serialize`) and `#[serde(default)]` on all generated prost messages so that JSON payloads can be deserialized directly into the request types. This reinstates the deserializers that were dropped in 8af3189 so that clients like `ldk-server-mcp` can parse tool arguments straight into the typed proto structs instead of threading every field through `serde_json::Value`. Generated with the assistance of AI (Claude).

Move the MCP bridge into the ldk-server workspace and switch it to an in-tree client dependency so workspace builds and tests cover it directly. Co-Authored-By: HAL 9000

Support storage.disk.dir_path config and fall back to the default gRPC address when neither LDK_BASE_URL nor a config file is present, matching the behavior of ldk-server-cli. Co-Authored-By: HAL 9000

Fix clippy needless_borrows_for_generic_args in test. Co-Authored-By: HAL 9000

Move routing and invoice default constants into ldk-server-client so they are shared between ldk-server-cli and ldk-server-mcp. Co-Authored-By: HAL 9000

Move the shared config loading and credential resolution logic into ldk-server-client so that ldk-server-cli and ldk-server-mcp both consume the same implementation instead of duplicating path handling, TOML parsing, and API-key hex-encoding in each binary. Generated with the assistance of AI (Claude).

Use hex-conservative's DisplayHex implementation for encoding the pathfinding scores blob instead of a hand-rolled hex formatter so the crate matches the hex encoding already used elsewhere in the workspace. Generated with the assistance of AI (Claude).

Dispatch tool invocations through a HashMap keyed by tool name rather than scanning the full registry on every call, and emit compact JSON for tool responses instead of pretty-printing so the MCP bridge doesn't spend tokens on insignificant whitespace when piping results to an agent. Generated with the assistance of AI (Claude).

Probe the ldk-server with a GetNodeInfo call during startup so bad credentials or an unreachable base URL surface right away instead of only being discovered on the first tool call. The probe only logs a warning if it fails so the JSON-RPC loop still serves `initialize` and `tools/list` responses when the server is temporarily down. Generated with the assistance of AI (Claude).

Advertise the `2025-11-25` MCP protocol revision so the bridge reports the current protocol version rather than the older `2024-11-05` spec. Generated with the assistance of AI (Claude).

Classify tool handler errors with a dedicated `McpError` type that maps `LdkServerError` variants onto JSON-RPC error codes (`INVALID_PARAMS` for invalid-request errors, `INTERNAL_ERROR` for auth, Lightning and internal failures) and reuse those codes at the dispatch boundary so a `tools/call` request missing its `name` parameter returns a real JSON-RPC error instead of being silently routed as an "unknown tool". Handlers now propagate `LdkServerError` through a `From` conversion rather than cloning the error message. Generated with the assistance of AI (Claude).

Use the proto-generated `Deserialize` impls to parse each tool's arguments directly into the typed request struct, dropping the per-field `serde_json::Value` scaffolding and the handcrafted helpers for `Bolt11InvoiceDescription`, `ChannelConfig`, `RouteParametersConfig` and page tokens. `expiry_secs` still gets the MCP-side 24h default when omitted; `sign_message` and `verify_signature` keep a manual arg path since their proto `bytes` field cannot be deserialized from a JSON string. Tool JSON schemas are updated to describe the now-nested shapes for invoice descriptions, route parameters, channel configs, and page tokens. Generated with the assistance of AI (Claude).

Use the workspace-built MCP binary directly in tests so regressions are caught without requiring a live server and without recompiling from inside each test. Generated with the assistance of AI (Claude).

Build the MCP binary in the e2e harness and exercise its stdio protocol against a live ldk-server so basic MCP functionality is verified without involving an agent. Co-Authored-By: HAL 9000

Drop the tests/ directory from rerun-if-changed since test changes don't affect the mcp binary. Co-Authored-By: HAL 9000

Advertise the bumped `2025-11-25` MCP protocol version in the e2e test's initialize call so its assertion lines up with the server, and pull in the `hex-conservative` dependency that `ldk-server-client` started transitively pulling through its shared config module. Generated with the assistance of AI (Claude).

Run MCP-specific formatting, clippy, and crate tests in a dedicated workflow and add a separate job that exercises the MCP e2e sanity suite on Ubuntu. Co-Authored-By: HAL 9000

Remove redundant formatting check (already covered by the main CI workflow) and drop the MCP e2e job (already covered by the e2e-tests workflow). Co-Authored-By: HAL 9000

Describe the MCP bridge as a first-class workspace member and document how to build, test, and sanity-check it alongside the rest of ldk-server. Co-Authored-By: HAL 9000

Replace exhaustive tool listing with a pointer to tools/list to avoid the maintenance burden of keeping the README in sync with every new RPC. Co-Authored-By: HAL 9000

tnull requested a review from benthecarman April 15, 2026 09:37

tnull marked this pull request as draft April 15, 2026 09:37

tnull force-pushed the 2026-04-move-mcp-into-workspace branch 2 times, most recently from 70f8e5f to 3bc8a6e Compare April 15, 2026 09:50

benthecarman reviewed Apr 15, 2026

View reviewed changes

Comment thread .github/workflows/mcp.yml Outdated

Comment thread .github/workflows/mcp.yml Outdated

Comment thread e2e-tests/build.rs Outdated

Comment thread ldk-server-mcp/src/tools/handlers.rs Outdated

Comment thread ldk-server-mcp/README.md

tnull force-pushed the 2026-04-move-mcp-into-workspace branch from 3bc8a6e to 8d6d7b0 Compare April 16, 2026 09:47

tnull requested a review from benthecarman April 16, 2026 09:47

tnull mentioned this pull request Apr 16, 2026

Add initial guides & documentation #186

Merged

tnull marked this pull request as ready for review April 16, 2026 11:03

benthecarman reviewed Apr 16, 2026

View reviewed changes

tnull force-pushed the 2026-04-move-mcp-into-workspace branch 2 times, most recently from b76ffeb to b0292ff Compare April 23, 2026 13:37

benthecarman reviewed Apr 26, 2026

View reviewed changes

tnull force-pushed the 2026-04-move-mcp-into-workspace branch from b0292ff to 9295c38 Compare April 27, 2026 13:41

github-advanced-security AI found potential problems Apr 27, 2026

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tnull added 13 commits April 27, 2026 15:44

Add ldk-server-mcp to the workspace

c9eb8f2

Move the MCP bridge into the ldk-server workspace and switch it to an in-tree client dependency so workspace builds and tests cover it directly. Co-Authored-By: HAL 9000

f - Add ldk-server-mcp to the workspace

74e47a1

Support storage.disk.dir_path config and fall back to the default gRPC address when neither LDK_BASE_URL nor a config file is present, matching the behavior of ldk-server-cli. Co-Authored-By: HAL 9000

f - Add ldk-server-mcp to the workspace

3febdfa

Fix clippy needless_borrows_for_generic_args in test. Co-Authored-By: HAL 9000

f - Add ldk-server-mcp to the workspace

1504096

Move routing and invoice default constants into ldk-server-client so they are shared between ldk-server-cli and ldk-server-mcp. Co-Authored-By: HAL 9000

f - Add ldk-server-mcp to the workspace

db41f1f

Advertise the `2025-11-25` MCP protocol revision so the bridge reports the current protocol version rather than the older `2024-11-05` spec. Generated with the assistance of AI (Claude).

f - Add ldk-server-mcp to the workspace

73f8c66

tnull added 8 commits April 27, 2026 15:44

Improve mcp test coverage in workspace

cfad53f

Use the workspace-built MCP binary directly in tests so regressions are caught without requiring a live server and without recompiling from inside each test. Generated with the assistance of AI (Claude).

Add end-to-end sanity checks for ldk-server-mcp

6758876

Build the MCP binary in the e2e harness and exercise its stdio protocol against a live ldk-server so basic MCP functionality is verified without involving an agent. Co-Authored-By: HAL 9000

f - Add end-to-end sanity checks for ldk-server-mcp

d94223f

Drop the tests/ directory from rerun-if-changed since test changes don't affect the mcp binary. Co-Authored-By: HAL 9000

Add CI coverage for ldk-server-mcp

df9f8d5

Run MCP-specific formatting, clippy, and crate tests in a dedicated workflow and add a separate job that exercises the MCP e2e sanity suite on Ubuntu. Co-Authored-By: HAL 9000

f - Add CI coverage for ldk-server-mcp

4ea7519

Remove redundant formatting check (already covered by the main CI workflow) and drop the MCP e2e job (already covered by the e2e-tests workflow). Co-Authored-By: HAL 9000

Document ldk-server-mcp in the workspace

f199a4c

Describe the MCP bridge as a first-class workspace member and document how to build, test, and sanity-check it alongside the rest of ldk-server. Co-Authored-By: HAL 9000

f - Document ldk-server-mcp in the workspace

9d74698

Replace exhaustive tool listing with a pointer to tools/list to avoid the maintenance burden of keeping the README in sync with every new RPC. Co-Authored-By: HAL 9000

tnull force-pushed the 2026-04-move-mcp-into-workspace branch from 9295c38 to 9d74698 Compare April 27, 2026 13:44

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tnull commented Apr 15, 2026

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