Blast-radius analysis for a symbol or file — shows all callers, type supertypes/subtypes, and reference count before you change it. Use when refactoring, deleting, or changing the signature of any function, type, or method. Also accepts a file path to surface all exported-symbol impact in one shot.
Blast-radius analysis for a symbol or file — shows all callers, type supertypes/subtypes, and reference count before you change it. Use when refactoring, deleting, or changing the signature of any function, type, or method. Also accepts a file path to surface all exported-symbol impact in one shot.
Blast-radius analysis for any symbol or file. Discovers all direct references,
callers (via call hierarchy), and type relationships before you touch anything.
Read-only — does not modify any files.
Run this skill before lsp-edit-export: impact tells you what exists and how
widespread the change is; lsp-edit-export tells you how to execute the change safely.
Invocation:
File path (e.g. "internal/lsp/client.go") → use the File-level entry (Step 0) to surface all exported-symbol impact at once.
Symbol name in dot notation (e.g. "codec.Encode", "Buffer.Reset") → skip Step 0; start at Prerequisites, then Step 1.
Step 0 — File-level entry (when user provides a file path)
Use this shortcut when the user is changing or auditing an entire file rather
than a single symbol. blast_radius enumerates all exported symbols in
the file, resolves their references, and returns test callers (with enclosing
test function names) and non-test callers in a single call.
mcp__lsp__blast_radius({
"changed_files": ["/abs/path/to/file.go"],
"include_transitive": false // set true to surface second-order callers
})
Returns:
affected_symbols — each exported symbol with its reference count
test_callers — test files + enclosing test function names
non_test_callers — production call sites
Decision after Step 0:
Result
Action
0 non-test callers
Low blast radius. Proceed with change.
Few callers, known files
Medium risk. Update each call site.
Many callers across packages
High risk. Consider staged rollout.
Want symbol-level detail
Continue to Steps 1–5 for any specific symbol.
Skip Steps 1–5 if the file-level summary is sufficient.
Prerequisites (for symbol-level Steps 1–5)
If LSP is not yet initialized, call mcp__lsp__start_lsp with the workspace
root first.
Check what the server supports before proceeding — find_callers and
are optional LSP features not implemented by all servers:
type_hierarchy
mcp__lsp__get_server_capabilities()
Note which tools appear in supported_tools. Steps 3 and 4 below depend on
this result.
Step 1 — Locate the symbol
Use go_to_symbol with the symbol name provided by the user:
symbol_path uses dot notation. For a top-level function Encode in package
codec, use "codec.Encode". For a method Reset on type Buffer, use
"Buffer.Reset".
Record the returned file, line, and column — you will pass them to
every subsequent step.
Step 2 — Enumerate all direct references (always available)
Call find_references with include_declaration: false to find every usage
site across the workspace:
mcp__lsp__find_references({
"file_path": "<file from Step 1>",
"position_pattern": "func @@SymbolName(", // adjust prefix for symbol kind
"include_declaration": false
})
Collect all reference locations. Group results by file. Record the total count
and list of files — these feed the Impact Report.
Only if find_callers appears in supported_tools from Step 0.
mcp__lsp__find_callers({
"file_path": "<file from Step 1>",
"line": <line from Step 1>,
"column": <column from Step 1>,
"direction": "incoming" // use "both" if callees are also needed
})
If find_callers is not in supported_tools, skip this step entirely.
Note "call hierarchy not supported by this server" in the Impact Report.
Step 4 — Type hierarchy (supertypes and subtypes)
Only applicable when the symbol is a type, interface, or class (not a
plain function or method). Only if type_hierarchy appears in supported_tools.
mcp__lsp__type_hierarchy({
"file_path": "<file from Step 1>",
"line": <line from Step 1>,
"column": <column from Step 1>,
"direction": "both"
})
If the symbol is a function or method: skip this step; note
"not applicable (function)" in the report.
If type_hierarchy is not in supported_tools: skip this step; note
"not supported by this server" in the report.
Reference count and list of files containing references
Callers from find_callers incoming (or skip note)
Supertypes and subtypes from type_hierarchy (or skip note)
Blast radius: count of distinct files affected
Then apply the decision guide:
Blast radius
Recommendation
0 references
Likely dead code. Confirm with lsp-dead-code before deleting.
1–5 files
Low risk. Proceed. Update all callers.
6–20 files
Medium risk. Plan changes carefully. Stage in waves.
> 20 files
High risk. Consider a deprecation path or feature flag.
Example
Goal: assess blast radius of exported function `ParseConfig` in pkg/config
Prerequisites — get_server_capabilities:
→ supported_tools: [go_to_symbol, find_references, find_callers, ...]
→ type_hierarchy: not in supported_tools
Step 1 — go_to_symbol: symbol_path="config.ParseConfig"
→ pkg/config/parser.go:42:6
Step 2 — find_references: position_pattern="func @@ParseConfig("
→ 7 references in 4 files
→ cmd/main.go, internal/app.go, internal/loader.go, pkg/config/parser_test.go
Step 3 — find_callers: direction="incoming"
→ callers: cmd.main (cmd/main.go:14), app.Start (internal/app.go:31), ...
Step 4 — type_hierarchy: skipped (function), also not supported by server
Step 5 — Impact Report:
## Impact Report: ParseConfig
- Kind: function
- Definition: pkg/config/parser.go:42:6
- References: 7 across 4 files
...
- Risk level: low
Note on position_pattern
position_pattern with @@ is a agent-lsp extension. If your MCP client
does not support it, fall back to explicit line and column parameters from
the location returned by go_to_symbol in Step 1.
