Slnmap (sln-map) — a semantic map of your .sln for AI coding agents.
Open source under the MIT license.
Your AI agent can't refactor .NET code it can't see. Ask an agent "what breaks if I change this interface?" and it guesses from the files in its context — missing callers in other projects and files it never opened. Slnmap gives the agent a precise, compiler-accurate map of your whole solution, so it answers correctly: every caller, every implementation, across every project. Fewer broken changes, no hallucinated dependencies. It runs locally and serves the map to your agent or editor over MCP.
1. Install the global tool (requires the .NET SDK 9.0+):
dotnet tool install --global Slnmap
If this is the first .NET global tool ever installed on the machine, the tools directory
(~/.dotnet/tools
) may not be on your PATH
yet — open a new terminal before running slnmap
.
2. Analyze your solution (or a single .csproj
) — this builds slnmap.db
in the current folder:
slnmap analyze path/to/YourSolution.sln
3. Connect your MCP client. For Claude Code, add this to .mcp.json
in your project. Use an
absolute path to the slnmap.db
you just built — an MCP client's working directory is usually not your project folder, so a relative path can silently resolve to the wrong (or a missing) file:
{
"mcpServers": {
"slnmap": {
"command": "slnmap",
"args": ["serve", "--db", "C:/path/to/your/project/slnmap.db"]
}
}
}
On macOS/Linux, use a POSIX absolute path instead, e.g. /home/you/project/slnmap.db
.
Or register it from the command line:
claude mcp add slnmap -- slnmap serve --db C:/path/to/your/project/slnmap.db
Restart your MCP client after registering.Fully quit and relaunch it — starting a new conversation or reconnecting mid-session is not enough; a running session will not see the new tools until the client process restarts.
That's it. Ask your agent an architecture question and it will call Slnmap.
(Run slnmap doctor
first if anything looks off — see Troubleshooting.)
The server exposes thirteen read-only tools. Give them fully qualified names; results are capped and counts-first. (A note the tools also carry: an FQN does not reveal whether a member is an explicit interface implementation.)
| Tool | Example question |
|---|---|
find_symbol |
|
"Find the IBasketService interface." |
|
get_dependencies |
|
"What does CartController.Index depend on?" |
|
impact_analysis |
|
"What breaks if I change IBasketService ?" |
|
get_architecture_overview |
|
| "Show me the projects and how they depend on each other." | |
find_usages |
|
"Where is BasketService.GetBasket used?" |
|
find_implementations |
|
"Who implements IBasketService / overrides this virtual member?" |
|
get_type_hierarchy |
|
"Show the base and derived type tree for BaseEntity ." |
|
find_tests_for_symbol |
|
"Which tests exercise BasketService.AddItemToBasket ?" |
|
get_project_dependencies |
|
| "How do the projects reference each other, and where is the coupling worst?" | |
find_circular_dependencies |
|
| "Are there dependency cycles between projects or namespaces?" | |
get_symbol_source |
|
"Show me the actual source of IBasketService ." |
|
list_endpoints |
|
"List every HTTP endpoint, or just the POST s under /api/basket ." |
|
find_endpoint |
|
"Which endpoint serves /api/basket/42/items , and which method handles it?" |
For an interface (or interface member), impact_analysis
follows both the interface's callers and its concrete implementations/overrides — so the answer includes code that only touches the interface, across projects, in files nobody has open.
HTTP endpoints are first-class graph nodes — from ASP.NET Core Minimal APIs (v0.7.0) and
attribute-routed controllers (v0.8.0): each MapGet
/MapPost
/… registration and each
[Route]
/[HttpGet("…")]
action appears as VERB /route/template
linked to its handler method,
so impact_analysis
and find_usages
on a handler surface the actual routes that break. Route
templates are resolved statically — MapGroup
prefixes, const
patterns, the common
CleanArchitecture registration conventions, class-level [Route]
(including inherited ones and
[controller]
/[action]
tokens), and controller base classes reached through packages
(Ardalis.ApiEndpoints works out of the box). Anything that can't be resolved statically is counted
and reported, never guessed — and controllers routed conventionally (MapControllerRoute
, no route attributes) are detected and disclosed rather than silently absent.
The exact parameter names, for clients that call the tools directly. Most tools take fqn
— the
symbol's fully qualified name — not symbol
, name
, or type
; a wrong parameter name fails the call.
| Tool | Parameters | Description |
|---|---|---|
find_symbol |
||
query (required), kind (optional) |
||
| Search symbols by name or FQN, case-insensitive substring; returns kind, FQN, and file for up to 20 matches. | ||
get_architecture_overview |
||
| (none) | ||
| Projects, project-to-project dependencies, node/edge counts by kind, and top-level namespaces. | ||
get_symbol_source |
||
fqn (required), context_lines (optional, 0–20, default 5) |
||
| Print a symbol's source, read from its file at the declaration span. | ||
find_usages |
||
fqn (required) |
||
| Where a symbol is called or referenced — containing member, file, and line, up to 50. | ||
get_dependencies |
||
fqn (required), direction (optional: , outgoing /incoming , default outgoing )depth (optional, 1–3, default 1) |
||
| A symbol's dependencies grouped by relationship kind (Calls, Implements, Inherits, References). | ||
find_implementations |
||
fqn (required) |
||
| Concrete types implementing an interface / deriving from a base, or members overriding a virtual/interface member. | ||
get_type_hierarchy |
||
fqn (required), direction (optional: , up /down /both , default both )depth (optional, 1–10, default 5) |
||
| Base and/or derived type tree as an indented text tree. | ||
get_project_dependencies |
||
project (optional, default all ) |
||
| Project-to-project reference map with cross-project reference counts and a hotspot line. | ||
impact_analysis |
||
fqn (required) |
||
| Every symbol that transitively depends on the given one (depth 5) — counts first, then nearest-first. | ||
find_tests_for_symbol |
||
fqn (required) |
||
| Test members that transitively exercise a symbol, grouped by project with file:line. | ||
find_circular_dependencies |
||
scope (optional: project /namespace , default project ) |
||
| Dependency cycles reported as path chains, worst offenders first. | ||
list_endpoints |
||
verb (optional: , GET /POST /PUT /DELETE /PATCH )prefix (optional route prefix, e.g. /api/vendors ) |
||
HTTP endpoints (Minimal APIs + attribute-routed controllers) grouped by project: VERB /route → handler — file:line ; unresolved registrations and conventionally-routed controllers disclosed in trailing notes. |
||
find_endpoint |
||
route (required: a template or a concrete path), verb (optional) |
||
Endpoints matching a route — case-insensitive, {param} holes bind concrete segments; a miss suggests near matches. |
slnmap analyze <solution> # build or update the code graph (incremental on re-run)
slnmap serve # serve the graph to MCP clients over stdio
slnmap status # show node/edge counts and when it was last analyzed
slnmap viz # export the graph as a self-contained interactive HTML file
slnmap doctor # check the environment can run Slnmap
These five verbs are the whole CLI. Symbol, usage, and impact querying is MCP-only — there is no
find
/usages
/impact
command; connect an MCP client to slnmap serve
to query the graph.
--db <path>
selects the database file (default slnmap.db
). -v
/--verbose
prints per-document progress on its own line per update — useful in an interactive terminal, but it floods piped or redirected output (logs, CI), so omit it there.
slnmap viz --output graph.html # export the whole graph
slnmap viz --project YourProject # export one project's subtree; others render as collapsed stubs
Opens as a single HTML file — double-click it, no server or internet connection required. It starts collapsed to one node per project; click a project, namespace, or class to drill into it. Like the rest of Slnmap, the export is self-contained: the graph library is embedded in the file, so nothing is fetched from a CDN and it works fully offline.
.NET tools do not update themselves, and Slnmap makes no network calls — so it will never nag you about (or check for) new versions. To update:
dotnet tool update -g Slnmap
To hear about releases, watch the GitHub repo (Watch → Custom → Releases); each release ships
with notes in the changelog. After a major-version update, re-run
slnmap analyze
if the tool asks for it — release notes call out when a graph rebuild is needed.
Slnmap is a standard .NET solution — clone, build, and test it with the SDK:
git clone https://github.com/EMahmoudNabil/slnmap.git
cd slnmap
dotnet build -c Release
dotnet test -c Release
To run the CLI without installing the global tool:
dotnet run --project src/Slnmap.Cli -- analyze path/to/YourSolution.sln
Analyzes C# solutions targeting .NET 8 and .NET 9 (earlier targets are untested — feedback welcome); runs on Windows, macOS, and Linux; works with any MCP client (tested with Claude Code).
100% local — and now you can verify it. Slnmap runs on your machine, reads your source with Roslyn, and writes a single local SQLite file. The MCP server reads only that local file. There is no telemetry, no network calls, and no cloud service — analysis works fully offline. Now that the CLI and MCP server are open source, that claim is auditable: read the code, or watch the process — nothing leaves your machine.
Measured on eShopOnWeb (10 projects,
net8.0
), .NET 9 SDK, on a 2-core laptop. Each timing is the median of 3 runs; full methodology, machine spec, and pinned commit are in BENCHMARKS.md.
| Metric | Result |
|---|---|
| Graph size | 1,332 nodes / 3,014 edges |
| Cold analyze (10 projects) | ~20.9 s (median of 3) |
| Re-analyze after a one-file change | ~18.7 s (median of 3 — see note) |
impact_analysis on IBasketService (29 dependents, last measured v0.5.0) |
|
| ~240–290 ms (end-to-end MCP round-trip) |
Numbers are for v0.6.0: fully-qualified type references (no using
shortcut) now produce edges, and events are modeled as graph nodes (see the changelog) — the fully-qualified- reference fix accounts for nearly all of this release's edge growth (89 of 92 new edges) versus v0.5.0 (1,311 / 2,922 edges). Timings are flat within normal run-to-run noise; the analyzer's per-document work is otherwise unchanged. Full before/after detail, including the v0.5.0 and v0.3.0 baselines, is in BENCHMARKS.md.
To estimate your own solution's cold analyze time, scale by size rather than anchoring on any single number above: field measurements on real-world solutions (antivirus real-time protection on, no exclusions) come out at roughly 55–60 seconds per 1,000 analyzed documents. Treat it as approximate — hardware and antivirus overhead move it either way.
Incremental re-analysis. Re-analysis re-walks only the changed file and its dependents, but each run still pays a full workspace load of the solution — because the CLI is run-and-exit and does not keep a warm workspace. In practice that means re-analysis is currently about as fast as a cold run, not faster. A resident ** watch mode** that keeps the workspace warm (targeting sub-second re-analysis) is the top item on the roadmap.
Run ** slnmap doctor** first — it checks the three things that actually block analysis and prints a fix for each:
$ slnmap doctor
[ok] .NET SDK: 1 SDK(s) installed; newest: 9.0.314 …
[ok] MSBuild workspace: Roslyn MSBuild workspace initialized …
[ok] Graph directory: Writable: /path/to/cwd
"No .NET SDKs are installed" / MSBuild fails to load projects. Slnmap analyzes viaMSBuildWorkspace
, which runs design-time builds using your installed .NET SDK. Install the SDK (not just the runtime) fromhttps://dotnet.microsoft.com/download. OnWindows, if projects still fail to load, install the** Visual Studio Build Tools**(or Visual Studio) so MSBuild and the targeting packs resolve.** Analysis reports warnings but finishes.**That is expected and safe: a project that can't be loaded (e.g. a missing SDK or targeting pack) is reported as a warning and skipped — Slnmap indexes everything thatdidload rather than failing the whole run (apartial load). By default these are condensed into a singleWarnings: N (M unique)
summary line; runslnmap analyze --verbose
for the full, grouped detail.The first analysis of a large solution takes a while. Cold analysis compiles every project once; as a rough guide from field measurements, expect around55–60 seconds per 1,000 analyzed documents(approximate). Re-runs are faster on graph work but still reload the workspace — see the performance note above. This is normal; the graph is cached inslnmap.db
between runs.Windows Defender (or other antivirus) slows analysis. Real-time protection scans every file Roslyn reads while compiling your solution. Adding an exclusion for your repository folder can speed analysis up, but changing exclusions requires local admin rights — corporate users without them may need an IT ticket. No exclusion is required for correctness: analysis completes fine without one, and the ~55–60 s per 1,000 documents guide above was measured with real-time protection on and no exclusions in place.Ensure the .NET global tools directory (slnmap: command not found
after install.~/.dotnet/tools
) is on yourPATH
, then open a new shell.
Slnmap uses the Roslyn compiler platform to build a precise semantic graph of your solution — every type and member, and the relationships between them (calls, implementations, inheritance, references). The graph is stored locally and served to your AI agent or editor over MCP. Updates are incremental and crash-safe: an interrupted run never corrupts your existing graph.
Slnmap is open source under the MIT license.
The CLI and MCP server are MIT-licensed and will stay that way. Future hosted or team-oriented features may be commercial.
For questions or to report an issue, open a GitHub issue or contact ** hello@slnmap.dev**. Contributions are welcome — see