MCP Tools

NestWeaver exposes 43 tools via the Model Context Protocol (MCP), giving AI coding agents structured access to the knowledge graph. Every tool accepts JSON parameters and returns structured JSON responses.

• Context A ranked neighborhood for a name, file, or project.
• Navigation Read a symbol, trace calls, or follow a question.
• Impact What a change reaches, including tests and dead code.
• Vault Notes, backlinks, tags, and the sources you indexed.
• Utility Staleness, sidecars, and custom metadata.

Cursor’s lite mode exposes six of these: brain_context, brain_search, brain_impact, brain_status, brain_guide, and detect_changes.

Setup

Run nestweaver setup to auto-configure your agent’s MCP connection. Supported agents:

• Claude Code — writes to .mcp.json in the project root
• Cursor — configures the MCP server in Cursor settings
• Aider — adds the MCP server to .aider.conf.yml
• Copilot CLI — registers the MCP endpoint
• Gemini CLI — configures via .gemini/settings.json
• Codex — registers the MCP server for OpenAI Codex
• Other MCP-compatible agents — use nestweaver mcp to start the server manually

Tool categories

Category	Tools	Purpose
Context	brain_context, code_context, brain_search, project_context, get_summary, brain_status, brain_guide, brain_diff	Retrieve ranked context from the knowledge graph
Code Navigation	read_symbols, regex_search, count_patterns, flow_trace, investigate, investigate_expand, investigate_hydrate	Navigate symbols, trace execution flows
Impact Analysis	blast_radius, brain_impact, affected_tests, dead_code, detect_changes, hub_nodes, bridge_nodes, clusters, cross_repo_contracts, contract_drift	Assess change impact and architectural risk
Vault & Notes	note_get, backlinks, brain_add_source, brain_remove_source, brain_broken_links, brain_orphan_documents, brain_topic_clusters, brain_tag_graph, brain_doc_stats, brain_memory_lint, brain_memory_consolidate, brain_memory_related	Query vaults, manage knowledge sources
Utility	stale_check, prune_stale, compact_embeddings, set_extension, unset_extension, query_extensions	Graph maintenance and custom metadata

Common parameters

Many tools share these filtering and output parameters:

Parameter	Type	Description
token_budget	integer	Approximate token cap for the response (chars / 4). Controls how much context is returned.
response_format	string	"concise" for names and relationships only; "detailed" (default) adds file paths, scores, and UIDs.
repos	string[]	Filter results to specific repository UIDs or names.
tags	string[]	Include only nodes tagged with any of these tags.
exclude_tags	string[]	Exclude nodes tagged with any of these tags.
path_prefix	string	Include only nodes whose file path starts with this prefix.
kinds	string[]	Filter by node kind: Symbol, Note, Section, Tag, Heading. Case-insensitive prefix match.
limit	integer	Maximum number of results to return. Total counts are always reported regardless of limit.

MCP vs CLI token costs

In subagents, hooks, and scripts, use the CLI (nestweaver context, nestweaver search --json) instead of MCP tools. The CLI returns precomputed answers without loading tool schemas into context, saving approximately 40—60% fewer tokens per query.

Utility tools

These tools handle graph maintenance and custom metadata. They are not covered on a separate sub-page due to their small number.

stale_check

Check whether the graph index is current. Compares each repo’s indexed git SHA with HEAD and checks that edges were built by the current resolver generation. A generation mismatch reports outdated_resolver.

No parameters required.

prune_stale

Remove all indexed repos and vaults whose source directories no longer exist on disk.

No parameters required.

set_extension

Attach custom key-value metadata to any node in a JSON sidecar alongside the database.

Parameter	Type	Required	Description
uid	string	Yes	Node UID to annotate.
key	string	Yes	Property name (e.g. "team_owner", "deprecated").
value	any	Yes	Property value — any JSON value. Overwrites existing.

query_extensions

Query custom metadata set via set_extension. Two modes: by uid (all properties for a node) or by key + value (find all nodes matching a property).

Parameter	Type	Required	Description
uid	string	No	Return all custom properties for this node. When provided, key and value are ignored.
key	string	No	Property name to filter by. Required when not using uid mode.
value	any	No	Value to match (exact match only). Required when key is provided.

unset_extension

Remove one custom property from one node.

Parameter	Type	Required	Description
uid	string	Yes	Node UID.
key	string	Yes	Property name to delete.

compact_embeddings

Reclaim embedding vectors left behind by deleted graph nodes. This does not re-embed the graph.

code_context is the code-only PageRank walk. File paths are seeds there. brain_context takes note titles, tags, symbol names, and UIDs.