spreadsheet-kit is the tool interaction service for agent-based spreadsheet usage.
It gives agents a safe, inspectable, token-efficient way to read, analyze, mutate, verify, and operationalize Excel workbooks without falling back to brittle UI automation.
If you want an agent to work with spreadsheets like a real system instead of a screenshot puppet, this is the stack.
spreadsheet-kit ships a unified spreadsheet interaction layer across four surfaces:
| Surface | Binary / Package | Mode | Best for |
|---|---|---|---|
| CLI | asp / agent-spreadsheet |
Stateless | One-shot reads, safe edits, pipelines, CI, agent tool calls |
| MCP server | spreadsheet-mcp |
Stateful | Multi-turn agent sessions, workbook caching, fork/recalc workflows |
| JS SDK | spreadsheet-kit-sdk |
Backend-agnostic | App integrations that can target MCP today and WASM/session backends over time |
| WASM runtime | spreadsheet-kit-wasm |
In-process | Experimental byte/session embedding for local runtimes |
Supported workbook modes:
.xlsx/.xlsm— read + write.xls/.xlsb— discovery/read-oriented workflows only
- deterministic JSON contracts
- schema and example discovery from the CLI itself
- explicit pagination and compact output modes
- machine-readable warnings and error envelopes
- dry-run first workflows
- stateless output modes and overwrite safety
- event-sourced session editing
- verification surfaces for proving downstream outcomes
- structural impact analysis before risky workbook changes
- region detection
- table and footer-aware append helpers
- template row / row band cloning
- formula-specific replace and diagnostics
- named range CRUD
- recalculation + diff + proof flows
- nested command groups with legacy alias compatibility
- token-efficient reads
- exact-cell inspection and layout inspection
- workflow helpers for the repetitive parts agents usually get wrong
The current surface is much stronger than a plain “read some cells” tool. Major capabilities now include:
aspas the primary CLI withagent-spreadsheetpreserved as a compatibility alias- grouped verification via
asp verify proofandasp verify diff - preview-first workflow helpers for:
write appendwrite clone-template-rowwrite clone-row-band
- formula-safe batch workflows with parse-policy diagnostics
- cell/layout/export/import inspection surfaces
- named range management (
write name define|update|delete) - formula-only replacement (
write formulas replace) - event-sourced session editing with log, branch, undo/redo, fork, apply, and materialize
- SheetPort manifest lifecycle + execution for contract-driven spreadsheet automation
npm i -g agent-spreadsheet
asp --helpInstalls both:
asp— primary commandagent-spreadsheet— compatibility alias
Downloads a prebuilt native binary for your platform. No Rust toolchain required.
# CLI
cargo install spreadsheet-kit --features recalc --bin asp --bin agent-spreadsheet
# MCP server
cargo install spreadsheet-mcpFormualizer (the native Rust recalc engine) is included by default.
# Read-only / slim
docker pull ghcr.io/psu3d0/spreadsheet-mcp:latest
# Write + recalc + screenshots
docker pull ghcr.io/psu3d0/spreadsheet-mcp:fullnpm i spreadsheet-kit-sdkDownload from GitHub Releases.
Published native assets include:
- Linux x86_64
- macOS x86_64
- macOS arm64
- Windows x86_64
# What sheets are here?
asp read sheets data.xlsx
# What regions/tables/parameter blocks does this sheet contain?
asp read overview data.xlsx "Model"
# What named items are available?
asp read names data.xlsx
# Read a structured region as a table
asp read table data.xlsx --sheet "Model"# Raw values for exact ranges
asp read values data.xlsx Model A1:C20
# Detail-view for targeted cells (value / formula / cached / style triage)
asp read cells data.xlsx Model B2 D10:F12
# Layout-aware rendering for a bounded range
asp read layout data.xlsx Model --range A1:H30 --render both
# Export a bounded range to csv or grid json
asp read export data.xlsx Model A1:H30 --format csv --output model.csvasp workbook copy data.xlsx /tmp/draft.xlsx
asp write cells /tmp/draft.xlsx Inputs "B2=500" "C2==B2*1.1"
asp workbook recalculate /tmp/draft.xlsx
asp verify proof data.xlsx /tmp/draft.xlsx --targets Summary!B2,Summary!B3 --named-ranges
asp verify diff data.xlsx /tmp/draft.xlsx --details --limit 50A representative label-mode lookup:
asp analyze find-value data.xlsx "Net Income" --mode label --label-direction belowasp analyze ref-impact data.xlsx --ops @structure_ops.json --show-formula-deltaThis is intentionally read-only. It surfaces shifted spans, absolute-reference warnings, token counts, and optional before/after formula samples.
# Stateless batch writes
asp write batch transform data.xlsx --ops @ops.json --dry-run
asp write batch style data.xlsx --ops @style_ops.json --dry-run
# Append rows into a detected region or table, respecting footer rows when present
asp write append data.xlsx --sheet Revenue --table-name RevenueTable --from-csv rows.csv --header --dry-run
# Clone one template row with preview-first planning
asp write clone-template-row data.xlsx --sheet Inputs --source-row 8 --after 8 --count 3 --dry-run
# Clone a contiguous row band repeatedly
asp write clone-row-band data.xlsx --sheet Forecast --source-rows 12:16 --after 16 --repeat 4 --dry-runasp session start --base data.xlsx --workspace .
asp session op --session <id> --ops @edit.json --workspace .
asp session apply --session <id> <staged_id> --workspace .
asp session materialize --session <id> --output result.xlsx --workspace .And when you need proper history and branching:
asp session log --session <id> --workspace .
asp session fork --session <id> scenario-a --workspace .
asp session undo --session <id> --workspace .
asp session redo --session <id> --workspace .
asp session checkout --session <id> <op_id> --workspace .# Discover candidate ports from workbook structure
asp sheetport manifest candidates model.xlsx
# Validate or normalize a manifest
asp sheetport manifest validate manifest.yaml
asp sheetport manifest normalize manifest.yaml
# Bind-check a workbook against a manifest
asp sheetport bind-check model.xlsx manifest.yaml
# Execute the manifest with JSON inputs
asp sheetport run model.xlsx manifest.yaml --inputs @inputs.jsonThe primary CLI is asp.
agent-spreadsheet remains available as a compatibility alias, so both of these are valid:
asp read sheets data.xlsx
agent-spreadsheet read sheets data.xlsxasp read ...asp analyze ...asp write ...asp workbook ...asp verify ...asp session ...asp sheetport ...
Legacy flat commands are still normalized to the new nested surface where practical. That makes migration easier for older prompts, docs, and automation.
When an agent is unsure of payload shape, it can ask the tool directly:
asp schema write batch transform
asp example write batch transform
asp schema session op transform.write_matrix
asp example session op transform.write_matrixThis is a core design principle: the surface should explain itself to the agent.
| Command | Purpose |
|---|---|
asp read sheets <file> |
List sheets with summary metadata |
asp read overview <file> <sheet> |
Detect regions, headers, and orientation |
asp read values <file> <sheet> <range> [range...] |
Pull raw values for exact A1 ranges |
asp read export <file> <sheet> <range> |
Export a bounded range to csv or grid json |
asp read cells <file> <sheet> <target> [target...] |
Inspect exact cells/ranges with value/formula/cached/style snapshots |
asp read page <file> <sheet> ... |
Deterministic sheet paging with next_start_row |
asp read table <file> ... |
Structured table/region read with deterministic next_offset |
asp read names <file> |
Named ranges, named formulas, and table items |
asp read workbook <file> |
Workbook-level metadata |
asp read layout <file> <sheet> |
Layout-aware rendering with widths, merges, borders, and optional ascii output |
Agents rarely need “the whole spreadsheet.” They need:
- the right region
- the right page
- the right cells
- just enough layout to understand intent
That is why the read surface combines region detection, structured reads, detail inspection, and explicit continuation.
| Command | Purpose |
|---|---|
asp analyze find-value <file> <query> |
Search by value or by label semantics |
asp analyze find-formula <file> <query> |
Text search within formulas |
asp analyze formula-map <file> <sheet> |
Summarize formulas by complexity/frequency |
asp analyze formula-trace <file> <sheet> <cell> <precedents|dependents> |
Dependency tracing with continuation |
asp analyze scan-volatiles <file> |
Find volatile formulas |
asp analyze sheet-statistics <file> <sheet> |
Density and type statistics |
asp analyze table-profile <file> |
Header/type/cardinality profiling |
asp analyze ref-impact <file> --ops @structure_ops.json |
Preflight structural edit impact without mutation |
Headless spreadsheet automation wins when it can explain consequences, not just execute mutations. ref-impact, formula-trace, and grouped diagnostics are all part of that story.
| Command | Purpose |
|---|---|
asp write cells <file> <sheet> ... |
Direct shorthand cell edits |
asp write import <file> <sheet> ... |
Import grid json or csv into a workbook range |
asp write append ... |
Footer-aware row append into a region or table |
asp write clone-template-row ... |
Clone one template row with preview-first planning |
asp write clone-row-band ... |
Clone a multi-row template band repeatedly |
asp write formulas replace ... |
Formula-only find/replace on a sheet/range |
| `asp write name define | update |
asp write batch transform ... |
Stateless transform pipeline |
asp write batch style ... |
Stateless style edits |
asp write batch formula-pattern ... |
Autofill-like formula application |
asp write batch structure ... |
Rows/cols/sheets/copy/move style mutations |
asp write batch column-size ... |
Column width operations |
asp write batch sheet-layout ... |
Freeze panes, zoom, page setup, print area |
asp write batch rules ... |
Data validation + conditional formatting |
Most mutating commands support a strict mode matrix:
--dry-run--in-place--output <PATH>
This matters for agents because it allows:
- dry-run planning
- non-destructive execution
- explicit overwrite control
Formula mutation is now a first-class surface:
asp write formulas replace data.xlsx Sheet1 --find '$64' --replace '$65' --dry-run
asp write formulas replace data.xlsx Sheet1 --find 'Sheet1!' --replace 'Sheet2!' --range A1:Z100 --output fixed.xlsxasp write name define data.xlsx RevenueInput 'Inputs!$B$2'
asp write name update data.xlsx RevenueInput 'Inputs!$B$2:$B$4' --in-place
asp write name delete data.xlsx RevenueInput --in-place| Command | Purpose |
|---|---|
asp workbook create <path> |
Create a new workbook |
asp workbook copy <source> <dest> |
Safe copy for edit workflows |
asp workbook recalculate <file> |
Recalculate formulas via the configured backend |
| Command | Purpose |
|---|---|
asp verify proof <baseline> <current> |
Prove target deltas and isolate new/resolved/preexisting errors |
asp verify diff <original> <modified> |
Summary-first grouped workbook diff with optional paged details |
Most spreadsheet automation tools stop at “the edit applied.”
spreadsheet-kit goes further:
- did the target cells change the way we expected?
- did the workbook introduce new errors?
- which changes were direct edits vs recalculation fallout?
- what changed overall, grouped in a way an agent can reason about?
This verification layer is a big part of why this project is a serious agent substrate rather than a utility script.
The session surface is for workflows that are too complex for a single stateless write.
- persistent editing state
- staged dry-run operations
- compare-and-swap apply semantics
- logs and replayability
- branch/switch/fork flows
- undo / redo / checkout
- explicit materialization back to a workbook file
asp session start --base model.xlsx --workspace .
asp session op --session <id> --ops @ops.json --workspace .
asp session apply --session <id> <staged_id> --workspace .
asp session materialize --session <id> --output result.xlsx --workspace .asp session log --session <id> --workspace .
asp session branches --session <id> --workspace .
asp session fork --session <id> experiment-b --workspace .
asp session switch --session <id> experiment-b --workspace .
asp session undo --session <id> --workspace .
asp session redo --session <id> --workspace .
asp session checkout --session <id> <op_id> --workspace .Use sessions when you want repeatability, auditability, and multi-step safety.
SheetPort is the workflow surface for turning workbook inputs/outputs into explicit machine contracts.
asp sheetport manifest candidates model.xlsx
asp sheetport manifest schema
asp sheetport manifest validate manifest.yaml
asp sheetport manifest normalize manifest.yamlasp sheetport bind-check model.xlsx manifest.yaml
asp sheetport run model.xlsx manifest.yaml --inputs @inputs.json --freeze-volatileUse this when you want a workbook to behave less like an opaque file and more like a declared service interface.
All commands default to JSON. Many also support:
--shape canonical
--shape compactPolicy:
- canonical keeps the full stable schema
- compact removes wrapper noise where the contract allows it while preserving continuation fields and command-specific semantics
Shape policy:
- Canonical (default): preserve the full response schema.
- range-values: returns a stable
values: [...]envelope in both canonical and compact modes. - range-values default encoding: dense JSON (
dense.encoding = "dense_v1") withdictionary+ run-lengthrow_runs. - range-values
--include-formulas: includes sparse formula coordinates in dense mode (dense.formulas), or a matrix in explicitjsonformat. - read-table and sheet-page: compact preserves the active branch and continuation fields (
next_offset,next_start_row). - formula-trace compact: omits per-layer
highlightswhile preservinglayersandnext_cursor.
# sheet-page continuation
asp read page data.xlsx Sheet1 --format compact --page-size 200
asp read page data.xlsx Sheet1 --format compact --page-size 200 --start-row 201
# read-table continuation
asp read table data.xlsx --sheet "Sheet1" --table-format values --limit 200 --offset 0
asp read table data.xlsx --sheet "Sheet1" --table-format values --limit 200 --offset 200- Inspect top-level
formatbefore reading payload fields. format=full: read top-levelrowsplus optionalheader_rowandnext_start_row.format=compact: readcompact.headers,compact.header_row,compact.rowsplus optionalnext_start_row.format=values_only: readvalues_only.rowsplus optionalnext_start_row.- Continuation is always driven by top-level
next_start_rowwhen present. - Global
--shape compactpreserves the activesheet-pagebranch; it does not flattensheet-pagepayloads.
Machine continuation example:
- Request page 1 without
--start-row. - If
next_start_rowis present, callsheet-pageagain with--start-row <next_start_row>. - Stop when
next_start_rowis omitted.
When the agent is unsure what to send, ask for a schema or example:
asp schema write batch rules
asp example write batch rules
asp schema session op structure.insert_rows
asp example session op structure.insert_rowsAll batch payloads use a top-level envelope object. Most commands require {"ops":[...]}; column-size-batch prefers {"sheet_name":"...","ops":[...]} and also accepts per-op sheet_name inside {"ops":[...]}.
- Minimal:
{"ops":[{"kind":"fill_range","sheet_name":"Sheet1","target":{"kind":"range","range":"B2:B4"},"value":"0"}]} - Advanced:
{"ops":[{"kind":"replace_in_range","sheet_name":"Sheet1","target":{"kind":"region","region_id":1},"find":"N/A","replace":"","match_mode":"contains","case_sensitive":false,"include_formulas":true}]}
- Minimal:
{"ops":[{"sheet_name":"Sheet1","target":{"kind":"range","range":"B2:B2"},"patch":{"font":{"bold":true}}}]} - Advanced:
{"ops":[{"sheet_name":"Sheet1","target":{"kind":"cells","cells":["B2","B3"]},"patch":{"number_format":"$#,##0.00","alignment":{"horizontal":"right"}},"op_mode":"merge"}]}
- Minimal:
{"ops":[{"sheet_name":"Sheet1","target_range":"C2:C4","anchor_cell":"C2","base_formula":"B2*2"}]} - Advanced:
{"ops":[{"sheet_name":"Sheet1","target_range":"C2:E4","anchor_cell":"C2","base_formula":"B2*2","fill_direction":"both","relative_mode":"excel"}]} relative_modevalid values:excel,abs_cols,abs_rows
- Minimal:
{"ops":[{"kind":"rename_sheet","old_name":"Summary","new_name":"Dashboard"}]} - Advanced:
{"ops":[{"kind":"copy_range","sheet_name":"Sheet1","dest_sheet_name":"Summary","src_range":"A1:C4","dest_anchor":"A1","include_styles":true,"include_formulas":true}]}
- Minimal (preferred):
{"sheet_name":"Sheet1","ops":[{"range":"A:A","size":{"kind":"width","width_chars":12.0}}]} - Advanced (preferred):
{"sheet_name":"Sheet1","ops":[{"target":{"kind":"columns","range":"A:C"},"size":{"kind":"auto","min_width_chars":8.0,"max_width_chars":24.0}}]} - Also accepted (harmonized shape):
{"ops":[{"sheet_name":"Sheet1","range":"A:A","size":{"kind":"width","width_chars":12.0}}]}
- Minimal:
{"ops":[{"kind":"freeze_panes","sheet_name":"Sheet1","freeze_rows":1,"freeze_cols":1}]} - Advanced:
{"ops":[{"kind":"set_page_setup","sheet_name":"Sheet1","orientation":"landscape","fit_to_width":1,"fit_to_height":1}]}
- Minimal:
{"ops":[{"kind":"set_data_validation","sheet_name":"Sheet1","target_range":"B2:B4","validation":{"kind":"list","formula1":"\"A,B,C\""}}]} - Advanced:
{"ops":[{"kind":"set_conditional_format","sheet_name":"Sheet1","target_range":"C2:C10","rule":{"kind":"expression","formula":"C2>100"},"style":{"fill_color":"#FFF2CC","bold":true}}]}
write batch formula-pattern clears cached results for touched formula cells; run workbook recalculate to refresh computed values.
Formula-aware commands support:
--formula-parse-policy fail|warn|offfail— abortwarn— continue and attach grouped diagnosticsoff— skip silently
This lets agents choose between strictness and progress depending on the workflow.
read values <file> <sheet> <range> [range...] [--format dense\|json\|values\|csv] [--include-formulas]read cells <file> <sheet> <target> [target...] [--include-empty]read page <file> <sheet> --format <full|compact|values_only> [--start-row ROW] [--page-size N]workbook create <path> [--sheets Inputs,Calc,...] [--overwrite]analyze find-value <file> <query> [--sheet S] [--mode value\|label] [--label-direction right\|below\|any]write batch transform <file> --ops @ops.json (--dry-run\|--in-place\|--output PATH)
Formula-writing commands emit optional provenance metadata for troubleshooting:
written_via: write path (edit,transform_batch,apply_formula_pattern)formula_targets: sheet/cell or sheet/range targets touched by formula writes
Debug compare workflow:
- Apply the same formula target via two paths.
- Compare
write_path_provenance.written_viaandformula_targetsin responses. - Use
inspect-cellsplusrecalculateto compare resulting behavior.
- Keep label columns (often column A) explicitly sized (roughly
24–36chars) to prevent clipping. - Apply consistent number formats by semantic type:
- Currency:
"$"#,##0.00_);[Red]("$"#,##0.00) - Percent:
0.0% - Integer/count:
#,##0
- Currency:
- Apply
sheet-layout-batchfreeze panes after header layout stabilizes.
JSON output is compact by default; use --quiet to suppress warnings.
Global --output-format csv is currently unsupported; use command-specific CSV options like read table --table-format csv.
The MCP surface is the stateful server version of spreadsheet-kit.
Use it when you want:
- workbook caching across calls
- fork lifecycle instead of stateless file replacement
- multi-turn agent workflows
- screenshots and richer server-side orchestration
Add to ~/.claude.json or project .mcp.json:
{
"mcpServers": {
"spreadsheet": {
"command": "spreadsheet-mcp",
"args": ["--workspace-root", "/path/to/workbooks", "--transport", "stdio"]
}
}
}{
"mcpServers": {
"spreadsheet": {
"command": "docker",
"args": [
"run", "-i", "--rm",
"-v", "/path/to/workbooks:/data",
"ghcr.io/psu3d0/spreadsheet-mcp:latest",
"--transport", "stdio"
]
}
}
}spreadsheet-mcp --workspace-root /path/to/workbooks
# -> http://127.0.0.1:8079 (POST /mcp)list_workbooksdescribe_workbooklist_sheetsworkbook_summarysheet_overviewsheet_pageread_tablerange_valuesnamed_rangessheet_stylesworkbook_style_summary
find_valuefind_formulasheet_formula_mapformula_tracescan_volatilestable_profilesheet_statisticsget_manifest_stub
- fork lifecycle
- checkpoints
edit_batchtransform_batchstyle_batchapply_formula_patternstructure_batchcolumn_size_batchsheet_layout_batchrules_batchrecalculateget_changesetsave_fork- staged-change management
screenshot_sheet
vba_project_summaryvba_module_source
The JS SDK is the app-facing integration layer.
It normalizes:
- method names
- input aliases
- output shapes
- typed capability errors
It is designed so an integration can target:
- MCP backends now
- WASM/session backends as they mature in embedded runtimes
Install:
npm i spreadsheet-kit-sdkThe Rust crate exists in this repository and provides a WASM-facing byte/session wrapper around the shared engine.
Current status:
- the crate exists and is tested in-repo
- it is not yet published as a general-purpose public package
- the npm
spreadsheet-kit-wasmdistribution remains planned
So the right framing today is:
- WASM is real inside the repo
- public distribution and broader packaging are still evolving
Formula recalculation is pluggable.
| Backend | How | Default | Best for |
|---|---|---|---|
| Formualizer | Native Rust engine | Yes | Fast default recalc with no external dependency |
| LibreOffice | Headless soffice |
Docker :full / explicit builds |
Maximum compatibility and screenshot flows |
Feature notes:
recalc-formualizeris enabled by defaultrecalc-libreofficeis available for LibreOffice-backed builds- read and many write flows still work without recalc; only recalculate itself requires a backend
Published at ghcr.io/psu3d0/spreadsheet-mcp:
| Image | Size | Recalc | Best for |
|---|---|---|---|
latest |
~15 MB | No | Read-only analysis and lightweight agent deployments |
full |
~800 MB | Yes | Write + recalc + screenshots |
Examples:
# Read-only
docker run -v /path/to/workbooks:/data -p 8079:8079 ghcr.io/psu3d0/spreadsheet-mcp:latest
# Write + recalc
docker run -v /path/to/workbooks:/data -p 8079:8079 ghcr.io/psu3d0/spreadsheet-mcp:fullspreadsheet-kit/
├── crates/
│ ├── spreadsheet-kit/ # shared engine + asp / agent-spreadsheet CLI
│ ├── spreadsheet-mcp/ # MCP server adapter
│ └── spreadsheet-kit-wasm/ # experimental WASM-facing wrapper
├── npm/
│ ├── agent-spreadsheet/ # npm CLI wrapper
│ └── spreadsheet-kit-sdk/ # JS SDK
├── docs/ # architecture and design docs
├── benchmarks/ # scenario budget regression harnesses
└── .github/workflows/ # CI, release, docker builds
| Package | Role |
|---|---|
spreadsheet-kit |
shared engine and CLI binaries |
spreadsheet-mcp |
stateful MCP transport + server surface |
spreadsheet-kit-wasm |
WASM-facing byte/session wrapper |
agent-spreadsheet |
npm wrapper for the CLI binary |
spreadsheet-kit-sdk |
JS SDK for MCP/WASM-style integrations |
Core ideas:
- one semantic core shared across CLI, MCP, session, and WASM-facing work
- region detection for structural awareness
- token-efficient defaults so agents do not over-read spreadsheets
- verification as a first-class feature rather than an afterthought
- workflow helpers for the common mutations that spreadsheet agents repeatedly struggle with
Token-efficient workflow reference:
Recommended progression:
- discover workbook + sheets
- detect regions / table-like structures
- inspect only the exact region or cells needed
- mutate with dry-run or session staging
- recalculate if needed
- verify proof and review grouped diffs
# Build everything
cargo build --release
# Run formatting, lint, and tests
cargo fmt --all -- --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspaceLocal MCP iteration:
WORKSPACE_ROOT=/path/to/workbooks ./scripts/local-docker-mcp.shOr point your MCP client directly at the local binary:
{
"mcpServers": {
"spreadsheet": {
"command": "./target/release/spreadsheet-mcp",
"args": ["--workspace-root", "/path/to/workbooks", "--transport", "stdio"]
}
}
}- CLI package README:
npm/agent-spreadsheet - Core crate README:
crates/spreadsheet-kit - MCP crate README:
crates/spreadsheet-mcp - JS SDK README:
npm/spreadsheet-kit-sdk - WASM wrapper README:
crates/spreadsheet-kit-wasm - Packaging/versioning notes:
docs/PACKAGING.md - Heuristics and region detection:
docs/HEURISTICS.md - Recalc architecture:
docs/RECALC.md
Apache-2.0


