Fw Context MCP

What it is

Build-aware code intelligence for agents working on embedded firmware. It builds a persistent semantic index from compile_commands.json and the libclang AST, then answers structural questions — callers, callbacks, function-pointer targets, preprocessor exclusions, inheritance — instead of making the agent reconstruct the program from file reads and text searches.

What you get

• Search that degrades gracefully — search_code runs FTS5 with a kind filter and, when that returns nothing, broadens through six documented fallback steps, tagging each result with which one matched
• Three search surfaces kept distinct: search_code finds symbols by name, search_bodies searches only what is between a function's braces, search_content searches anywhere in files
• Call-graph queries — find_callers, find_references, find_call_path, find_all_callers_recursive, find_callees_recursive, find_dead_code, find_hotspots, find_wrapper_callers
• The indirect layer that text search cannot reach — find_indirect_call_sites, find_indirect_targets, trace_data_flow
• C++ structure — get_inheritance_chain, get_class_members, get_template_instances, get_method_overrides
• Build awareness — get_active_build, list_variants, check_dependencies, get_environment_status, so a multi-variant project is queried per variant or across all with variant: "*"
• Source retrieval and explanation — lookup_symbol, get_source, get_symbol_context, get_file_map, explain_symbol, read_file, smart_search, semantic_search, find_variables

Requirements

Python 3.11 or newer, libclang, a project that can produce compile_commands.json, and an MCP-capable agent. Install with pip install fw-context-mcp (version 0.27.6, stdio), then fw-context init in the project and fw-context index --build to build and index. Indexing is incremental by default — only changed translation units are re-parsed; --build forces a clean build, --force bypasses mtime checks. Ollama is optional and only powers local semantic enrichment and symbol explanations; the compiler-derived core index does not need it.

Setup effort

One command — pip install fw-context-mcp

Tools you get

38 tools named in the project's documentation.

Requires

• pip on PATH
• Python 3.11 or later