Microsoft Excel (Microsoft Graph workbook API)

# Fix list: Microsoft Excel (Microsoft Graph workbook API)

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/microsoft-excel-graph, the October 2026 research run, assessed 8 October 2026. Grade C, 58.5 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Microsoft Excel (Microsoft Graph workbook API): work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Payments & pricing, 15 out of 100, up to 10.6 more on the total

Why it scored 15: No x402, MPP or L402 (0). Workbook calls aren't on Microsoft's metered API list, so there is no per-call charge, but the file's home needs a Microsoft 365 licence and the plan price page refused our reader today (10). The free E5 developer sandbox is limited to Visual Studio subscribers and named partner programmes. The overview says consumer OneDrive isn't supported, while some reference pages list personal accounts (5). A person registers an app in Entra and signs in to consent (0).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 2. Reliability, 62 out of 100, up to 7.6 more on the total

Why it scored 62: A public Microsoft service health page at status.cloud.microsoft. It renders only with JavaScript, so we couldn't read components or history (20). No readable incident history (5). Excel resources are throttled at 5,000 requests per 10 seconds per app across all tenants and 1,500 per app per tenant, under a global 130,000 per 10 seconds, though Microsoft adds that the cost of a workbook call varies too much for the numbers to tell the whole story (15). Throttled responses carry `Retry-After`, the error guide gives a retry instruction per error code, and Microsoft asks for one request at a time per workbook. There is no idempotency key, and the row-add page says to repeat the request on a 504, which can add rows twice (12). No SLA naming the Graph API was found, and we didn't read the Online Services SLA document (0). The workbook endpoints are generally available on v1.0 (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 3. Security & auth, 65 out of 100, up to 6.1 more on the total

Why it scored 65: OAuth 2.0 through Entra ID with scoped, revocable consent. The workbook reference pages list delegated permissions only, and a Files.ReadWrite token reaches every file its user can open (27). The overview names Files.Read for reads while the reference pages give Files.ReadWrite as least privileged even for a range read. A non-persistent session keeps changes out of the file. Per-file Selected scopes exist for OneDrive and SharePoint, but the workbook pages don't list them. Nothing asks for confirmation before a delete (12). Cell contents written by other people reach the caller with no injection guidance in the workbook docs (0). Graph activity logs record app, user, URI and status for every request, but need Entra ID P1 or P2 and an Azure log destination (12). Microsoft 365 bounty of $1,250 to $19,500, a coordinated disclosure policy and an Office 365 SOC 2 Type 2 report. microsoft.com's security.txt passed its Expires date on 23 September 2026, and a token-leak fix in the JavaScript client is unreleased on npm (14).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 4. Agent ergonomics, 73 out of 100, up to 4.4 more on the total

Why it scored 73: A range is read by address, `$select` trims the properties returned and table rows take `$top` and `$skip`. A range answer carries values, text, formulas and number formats unless trimmed, and the whole-Graph OpenAPI is 44 MB (20). `$top` and `$skip` paging on table rows, plus server-side table sort and filter that change the workbook's own view (15). Errors carry a top-level code, a second-level code with a written instruction on whether to retry, and a request ID (18). No idempotency key on writes. Non-persistent sessions let an agent try edits without saving, and Microsoft's advice is sequential requests per workbook (8). Sessionless calls work with a bearer token and a file path, worksheet and chart IDs need their braces URL-encoded, and official SDKs cover C#, Java, Go, PHP, Python, PowerShell and JavaScript, though the npm JavaScript client dates from September 2023 (12).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 5. Maintenance & community, 53 out of 100, up to 4.1 more on the total

Why it scored 53: msgraph-sdk 1.64.0 reached PyPI on 6 October 2026, but the last Workbooks and charts entry in the Graph changelog is dated 19 September 2025 and the overview page March 2024. We scored this line between the two, a departure from the checklist's single date (10). Six Python SDK releases since 14 July 2026, from 1.59.2 to 1.64.0 (20). A public changelog and SDK issue trackers. The seven newest open issues on msgraph-sdk-python had no or one reply, and a security fix merged into the JavaScript client on 16 June 2026 hasn't reached npm (7). Current SDKs in most languages, with the JavaScript client the exception at 3.0.7 from September 2023 (10). Active releases on the Python package, none on the JavaScript one (6).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## 6. Schema & documentation, 85 out of 100, up to 2.4 more on the total

Why it scored 85: OpenAPI 3.0.4 for all of Graph v1.0 in microsoftgraph/msgraph-metadata, with 1,442 workbook paths and 1,765 operations (25). learn.microsoft.com has no llms.txt, but every docs page we asked for with `accept=text/markdown` came back as Markdown (10). Reference pages state the purpose and the permissions of each call, and the overview explains sessions, nulls, unbounded and large ranges. Pages disagree on whether personal accounts and Files.Read work, and the workbookOperation page opens with a line that explains little (14). Cell values, formulas and number formats are untyped JSON (`values: { }` in the OpenAPI), and chart types are plain strings (7). An HTTP example on each page, plus separate pages for error codes and error handling (14). v1.0 and beta, with a dated public changelog (15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 7. Transparency & trust, 75 out of 100, up to 2.2 more on the total

Made of editorial 65, provenance 85.

Why it scored 75: Closed service under the Microsoft APIs terms of use, last updated October 2025, with MIT SDKs (15). Microsoft's data handling page for Microsoft 365 gives at most 30 days after active deletion and 180 days after a subscription ends for customer content, Excel files included, and the privacy statement was updated in September 2026. We didn't read the DPA (22). The Graph policy is at least 24 months' notice before a GA API or version is removed, with breaking changes only on a new version number (18). Data residency for Microsoft 365 is documented by tenant geography. The sub-processor list sits on the Service Trust Portal, which we didn't read (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- Terms of service: read, states 5 of the 7 things a reader expects, and has 3 clauses that cost points (2.3 of 10)
- Privacy policy: read, states 8 of the 8 things a reader expects, and has 1 clause that costs points (8 of 10)
- security.txt: published but past its Expires date (5 of 10)

## Deductions

Each comes off the total. A fixed and documented problem counts for less at the next check.

- 2026-06-16: a fix for a token leak through URL userinfo host confusion was merged into msgraph-sdk-javascript and the version set to 3.0.8, but npm still served 3.0.7 on 8 October 2026 and the repository lists no published advisory. Exploiting it needs an attacker-influenced URL passed to the client, and it affects agents that call the workbook API through that client (https://github.com/microsoftgraph/msgraph-sdk-javascript/commit/5438ae90f50ef15d3656f0cf9c5485deee351f19, https://registry.npmjs.org/@microsoft/microsoft-graph-client/latest)

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- unchecked: status page components and incident history, which need JavaScript
- unchecked: Microsoft 365 plan prices, because the pricing page refused our reader
- unchecked: the Online Services SLA document, the DPA and the sub-processor list on the Service Trust Portal
- Whether application permissions and the per-file Selected scopes work on workbook endpoints. The reference pages say application permissions aren't supported
- Whether personal Microsoft accounts work. The overview says consumer OneDrive isn't supported, while the range and list-rows pages list Files.ReadWrite for personal accounts
- Whether Microsoft will publish msgraph-sdk-javascript 3.0.8 or an advisory for the 16 June 2026 fix
- First release date of the workbook API, not established

## Weaknesses

- Reference pages list delegated permissions only and mark application permissions as not supported
- Files.ReadWrite is the least privileged permission on the reference pages, even for reading a range or listing rows
- No idempotency key on writes. The row-add page says to repeat the request on a 504
- Cell values, formulas and number formats are untyped JSON in the OpenAPI
- The last Workbooks and charts changelog entry is dated 19 September 2025, and the overview page is dated March 2024

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Create a session with POST /workbook/createSession and send `workbook-session-id` on every call. Persistent sessions expire after about 5 minutes idle
- Set `persistChanges` to false when you only need a calculation or a chart image, so nothing is saved to the file
- Send one request at a time per workbook and wait for each response. Microsoft warns that parallel writes cause throttling, timeouts and merge conflicts
- Add rows in one call with a two-dimensional `values` array, and check the table before repeating a row add that returned 504
- Read bounded addresses such as A1:D500. A whole-column range such as C:C returns null for values, and writes to it are refused

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.