Transactional refactoring MCP with 11 evidence-backed tools, hash-bound previews, and rollback.
Transactional refactoring MCP with 11 evidence-backed tools, hash-bound previews, and rollback.
weavatrix-refactor · v0.1.5 (latest)
by Sergii-ziborov
weavatrix-refactor
Evidence-backed, transactional refactoring for coding agents.
weavatrix-refactor is the write-capable member of the Weavatrix family. It
combines the complete read-only weavatrix-js code-intelligence MCP with 11
refactoring tools that can prove a change, preview it against the current
working tree, apply it atomically, refresh the graph, and roll it back.
It is substantially more than a rename wrapper:
- semantic JS/TS rename through the bundled language server;
- SQL table and field rename with schema-aware evidence;
- strict graph-plus-lexical rename for Python, Rust, Go, Java, C#, and Solidity;
- several related JS/TS renames merged into one atomic transaction;
- signature, symbol-body, import, bulk-replace, move, and delete-safety workflows;
- byte-exact file hashes,
beforetext, provenance, uncertainty, and graph revision in every applyable plan; - stale-tree detection, repository locking, rollback bundles, and automatic rollback after a mid-write failure;
- architecture and cycle projection before structural moves;
- post-change blast-radius and verification tools inherited from the core.
Why this is a separate package
The MIT weavatrix-js core is physically read-only: its published artifact has no
repository source-write path. This package is the explicit write
boundary. Installing it and selecting its refactor profile makes the edit
capability visible; without this package, the server cannot modify source.
The split is a safety property, not packaging cosmetics:
weavatrix-js core weavatrix-refactor repository
read-only evidence -> plan + preview + confirmation -> atomic write
graph / LSP / audit hashes / provenance / rollback refreshed graph
Architecture
The implementation is a ports-and-adapters system with one-way boundaries:
edit-plan model <- filesystem / lock / token adapters
^ ^
| |
plan engines -> preview / apply / rollback workflows -> MCP adapter
- Model validates the frozen
weavatrix.edit-plan.v1envelope and applies byte-exact edits as pure string transformations. - Platform adapters own real-path containment, atomic replacement, repository locks, single-use tokens, and durable rollback bundles.
- Plan engines compute rename, signature, symbol, import, move, delete, and bulk-replace evidence without owning the write workflow.
- Application workflows bind a preview to the current repository, issue and consume confirmation tokens, apply under a lock, and restore on failure.
- MCP adapter composes the 11 refactor tools with the read-only
weavatrix-jscatalog and exposes one stdio server.
The checked-in strict architecture contract enforces zero runtime cycles, files no longer than 300 lines, and functions no longer than 100 lines. It has no exceptions or ratchet baseline.
What makes the refactor workflow different
An ordinary editor rename answers: "Which text edits should I make now?" Weavatrix Refactor also answers:
| Question | Evidence returned |
|---|---|
| Is this the exact symbol? | Stable graph symbol id plus parser/LSP selection range |
| Which references are proven? | Per-edit provenance: EXACT_LSP, RESOLVED, EXTRACTED, or LEXICAL_EXACT |
| What was not proven? | Explicit uncertainReferences, notModified, warnings, and PARTIAL completeness |
| Did the tree change after preview? | File sha256 plus exact before text rechecked under the write lock |
| Can several renames partially succeed? | No. Related renames are conflict-checked and applied as one transaction |
| What happens after a disk/write failure? | Already-written files are restored; a durable rollback bundle remains |
| Will a move worsen architecture? | Projected runtime cycles, boundary violations, improvements, and blast radius |
| Did the refactor preserve behavior-shaped structure? | Refreshed graph plus verified_change caller/import/reference conservation |
The system fails closed when proof is insufficient. It never upgrades an
INFERRED edge into an applyable edit and never hides an ambiguous reference.
The complete rename workflow
rename_symbol and rename_related_symbols are complete operations, not
PLANNED-only helpers. Each method owns both phases.
1. Preview
Call the rename method normally:
{
"symbol": "src/users.ts#getUser@12",
"new_name": "getCustomer"
}
The method computes the rename, validates every plan file against the working
tree, and returns PREVIEW_OK with a short-lived confirmToken. Preview never
writes source and does not require the environment write gate.
2. Apply through the same method
Repeat the same operation inputs and add the confirmation:
{
"symbol": "src/users.ts#getUser@12",
"new_name": "getCustomer",
"mode": "apply",
"confirm_token": "<token from preview>"
}
The tool recomputes the deterministic plan, verifies that the token belongs to
that plan and repository, takes the repository lock, rechecks hashes and
before text, writes a rollback bundle, and applies every edit bottom-up.
The same contract applies to a coordinated set:
{
"renames": [
{"symbol": "src/api.ts#getUser@8", "new_name": "getCustomer"},
{"symbol": "src/api.ts#getOrder@20", "new_name": "getPurchase"}
]
}
rename_related_symbols detects overlapping edits, chains, swaps, shadowing
risk, and per-sub-rename failure before it issues a token. Apply is one atomic
multi-file operation.
Refactoring tools
Complete write workflows
| Tool | What it actually does |
|---|---|
rename_symbol |
Cross-language preview/confirm/apply rename. Dispatches to exact JS/TS LSP, SQL schema, or strict graph+lexical backends; returns honest backend completeness and every uncovered reference. |
rename_related_symbols |
Coordinates up to 50 JS/TS symbol renames in one shared language-server session and one atomic edit plan. Detects conflicts, chains, swaps, snapshot drift, and any failed sub-rename before writing. |
apply_edit_plan |
Generic two-phase executor for weavatrix.edit-plan.v1 envelopes from the other tools or weavatrix-online. Preview issues a plan-bound token; apply writes atomically with rollback. |
rollback_last_apply |
Restores the latest pre-apply bundle. Refuses if post-apply files drifted; retries converge after an incomplete restore. |
Proven plan producers
| Tool | What it actually does |
|---|---|
change_signature |
Adds or removes a JS/TS function or method parameter. Performs byte-exact declaration and call-argument surgery; spread calls and value-requiring additions remain explicit uncertainty. |
edit_symbol |
Uses the indexed parser range for replace_symbol_body, insert_before_symbol, or insert_after_symbol. JS/TS output is parse-gated; line endings and UTF-16 coordinates are preserved. |
bulk_replace |
Two-stage, occurrence-selective replacement over indexed files. First returns stable occurrence ids; the second call accepts chosen ids or an exact expected count and emits a hash-bound plan. Literal mode is the default; regex replacements use real capture expansion. |
organize_imports |
Removes only provably unused named JS/TS imports. Default and namespace imports stay uncertain; side-effect imports are untouched; sorting is deliberately left to the formatter. |
These plans are applied with apply_edit_plan, using the same preview, token,
atomic-write, and rollback protocol as rename.
Structural review and safety tools
| Tool | What it actually does |
|---|---|
move_file |
Builds a JS/TS relocate review: rewrites importer specifiers and the moved file's own relative imports, then projects architecture effects. File renaming itself remains an explicit editor/agent action, so this is intentionally not an apply envelope. |
move_symbol |
Projects a declaration move without inventing byte edits. Reports introduced/removed runtime cycles, target-file dependencies, architecture violations or improvements, and blast radius. |
delete_readiness |
Returns safe: true, false, or UNPROVEN with known references, dynamic/reflection risks, confidence, and the declaration span. Exported symbols are capped at UNPROVEN; deletion is never automated. |
Language and proof matrix
| Surface | Backend | Applyable provenance | Completeness contract |
|---|---|---|---|
| JavaScript / TypeScript rename | Bundled TypeScript language server | EXACT_LSP |
COMPLETE only when the language-server result and repository boundary are complete |
| SQL table rename | Schema-aware SQL scanner across SQL and host files | EXTRACTED / LEXICAL_EXACT |
Reports every skipped or ambiguous reference |
| SQL field rename | Definition-safe SQL backend | Proven definition edits only | Usages remain UNPROVEN rather than guessed |
| Python / Rust / Go / Java / C# / Solidity rename | Indexed graph references plus exact lexical location on the recorded line | EXTRACTED / LEXICAL_EXACT |
Always PARTIAL; ambiguous lines are never edited |
| JS/TS signature and imports | Parser plus graph call/reference evidence | EXTRACTED / RESOLVED |
Explicitly partial where graph reach cannot prove absence |
| Symbol-anchored edit | Indexed parser ranges for every indexed language | EXTRACTED |
JS/TS parse gate; other languages retain the parser-range evidence boundary |
Edit-plan proof envelope
Every applyable plan uses weavatrix.edit-plan.v1. Its load-bearing fields are:
- operation and graph revision;
- repository-relative target paths only;
- sha256 of every target file;
- exact 1-based line and UTF-16 character ranges;
- exact
beforeandaftertext; - per-edit provenance;
uncertainReferences,notModified, warnings, and completeness.
The applier additionally protects against:
- absolute paths, traversal,
.gitcasing/trailing-dot tricks, NTFS streams, and escaping symlinks/junctions; - non-UTF-8 or oversized files;
- overlapping edits, stale ranges, lone surrogates, and edits that split surrogate pairs;
- two writers interleaving in the same repository;
- token reuse, expiry, repository mismatch, or plan mismatch;
- partial writes and incomplete rollback.
createdAt is provenance metadata and is the only field excluded from the
confirmation fingerprint. This allows a rename method to recompute the same
plan on its apply call; every executable field remains token-bound.
Result states agents can act on
| State | Meaning |
|---|---|
PREVIEW_OK |
Every hash and before text matches; a single-use token was issued. |
PREVIEW_BLOCKED |
The generated plan does not match the current tree; nothing can be applied. |
WRITE_GATE_CLOSED |
The server was not deliberately started with source edits enabled. |
APPLIED |
Every planned edit was written and the rollback bundle is available. |
STALE |
The working tree changed between preview and the locked apply check; nothing was written. |
TOKEN_UNKNOWN / TOKEN_EXPIRED / TOKEN_*_MISMATCH |
Confirmation is absent, consumed, expired, or belongs to another plan/repository. |
REPO_BUSY |
Another apply or rollback currently owns the repository lock. |
ROLLED_BACK |
A failed apply or explicit rollback restored the original files. |
ROLLBACK_INCOMPLETE |
Restoration was blocked for named files; the durable bundle remains retryable. |
INVALID_PLAN |
Schema, path, range, encoding, overlap, or provenance validation failed before writing. |
Planner-specific states such as NOT_FOUND, NO_CHANGE, CONFLICT,
BLOCKED, UNPROVEN, and NOT_SUPPORTED remain visible instead of being
collapsed into a generic failure.
The three write gates
Repository source changes require all three:
weavatrix-refactoris installed and therefactorprofile selectsedit;- the server starts with
WEAVATRIX_ALLOW_SOURCE_EDITS=1; - the apply call presents a valid, unexpired, single-use token bound to the exact plan and repository.
Preview and every read-only analysis remain available while the environment gate is closed.
End-to-end change proof
The package includes all 34 read-only core tools in the same MCP server. A strong refactor session can therefore stay in one evidence chain:
inspect_symbol,context_bundle, orget_dependentsidentifies the exact target;rename_symbol,change_signature,move_symbol, or another refactor tool previews the change;- the write workflow applies atomically;
- the next graph call auto-refreshes changed files and reverse importers;
verified_changecompares callers, imports, and references against the merge base;change_impact,verify_architecture,coverage_map,run_audit, andfind_duplicatesinspect the consequences.
Useful inherited surfaces include:
- architecture maps and navigation:
module_map,query_graph,shortest_path,context_bundle; - impact and proof:
change_impact,get_dependents,prepare_change,verified_change; - health:
run_audit,find_dead_code,find_duplicates,coverage_map,hot_path_review; - contracts:
list_endpoints,trace_endpoint,trace_api_contract; - target architecture:
get_architecture_contract,verify_architecture,explain_architecture_violation; - repository control:
open_repo,rebuild_graph,graph_diff,list_known_repos.
See the weavatrix-js README for the complete JavaScript host catalog.
Run it
Start the merged read-only-plus-refactor MCP server for one repository:
npx -y weavatrix-refactor <repoRoot>
For an MCP client, the minimal configuration is:
{
"mcpServers": {
"weavatrix": {
"command": "npx",
"args": ["-y", "weavatrix-refactor", "/absolute/path/to/repository"]
}
}
}
On Windows, use npx.cmd when the client does not resolve command shims.
With no environment override, every analysis and preview tool works but source
writes fail closed. Add "env": {"WEAVATRIX_ALLOW_SOURCE_EDITS": "1"} only
for a session in which apply and rollback are deliberately authorized.
Applications that already host weavatrix-js can compose the same extension:
import {startMcpServer} from 'weavatrix-js/mcp-runtime'
import {refactorExtension} from 'weavatrix-refactor/extension'
await startMcpServer({
defaultCapabilities: 'refactor',
loadExtensions: async () => [refactorExtension()],
})
The exported extension registers tools and the refactor capability profile;
it does not silently open the write gate.
Scope and honest limits
- Related multi-symbol rename is currently JS/TS-only.
move_filecannot rename the file throughapply_edit_plan; it is a review plan because file relocation has different filesystem semantics.move_symbolis a topology/architecture dry-run, not byte-edit synthesis.- Graph+lexical language backends cannot prove reference completeness and stay
PARTIALeven when every known reference was located. delete_readinessnever auto-deletes, and public/exported APIs cannot receive an automatic clean verdict.- Tests, typechecking, runtime checks, and human review remain the release authority. Weavatrix supplies bounded evidence; it does not fabricate proof.
Package boundary
| Package | License | Responsibility |
|---|---|---|
weavatrix-js |
MIT | Read-only JavaScript graph, analysis, evidence, architecture, and verification |
weavatrix-refactor |
MIT | Proven refactor plans, transactional writes, and rollback |
weavatrix-online |
MIT | Explicit public network connector and remote plan/evidence workflows |
The refactor package extends the legacy JavaScript core only through
weavatrix-js/extension-api and weavatrix-js/analysis-kit; it does not copy
or relicense that core. The canonical weavatrix package is the native Rust
engine and is not this JavaScript extension host.
License
MIT.