Azure Blob Storage

# Fix list: Azure Blob Storage

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/azure-blob-storage, the October 2026 research run, assessed 8 October 2026. Grade BB, 75.7 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 Azure Blob Storage: 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, 20 out of 100, up to 10 more on the total

Why it scored 20: No x402, MPP or L402 (0). Per-GB and per-operation prices are public through the Azure Retail Prices API, while the pricing page fills its numbers by script (20). The Azure free account needs a credit or debit card, and no free Blob Storage allowance could be read (0). A person signs up in a browser with a phone number and a card (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. Security & auth, 81 out of 100, up to 3.3 more on the total

Why it scored 81: Microsoft Entra ID OAuth 2.0 tokens with Azure roles, managed identities on Azure, and user delegation signatures limited to seven days. Account access keys with full access are accepted until the owner disallows Shared Key. A SAS travels in the URL query string. It is a signature over stated permissions and an expiry, not the account key, so we read it as we read S3 presigned URLs and take no deduction, though Microsoft's docs say to protect a SAS like an account key (28 of 30). Storage Blob Data Reader for read-only work, roles on one container, attribute conditions, soft delete of 1 to 365 days, immutability policies and legal holds. Nothing asks for approval on a write or delete (17 of 20). The service returns whatever bytes were stored, and no guidance on treating blob contents as untrusted was found (8 of 15). Resource logs record reads, writes and deletes with caller IP address, but only after the owner adds a diagnostic setting (12 of 15). MSRC coordinated disclosure and bounty policies and a SOC 2 Type 2 report covering Azure. The microsoft.com security.txt passed its Expires date on 23 September 2026, and the audit scope page we loaded did not name services (16 of 20).

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.

## 3. Agent ergonomics, 84 out of 100, up to 2.6 more on the total

Why it scored 84: API reading, since Blob Storage has no MCP server of its own. List Blobs caps a page at 5,000 items, returns metadata, tags, versions and snapshots only when `include` asks, and Get Blob takes a `Range`. Responses are XML with no field selection (20 of 25). Paging by `marker` and `NextMarker`, `prefix` and `delimiter` filters, and Find Blobs by Tags (20). Errors carry a code and a message, 70-odd Blob codes are documented, and a 503 says which account limit was passed (16 of 20). Conditional headers, leases and soft delete make retries and mistakes recoverable. `x-ms-client-request-id` correlates logs and is not an idempotency key. The Azure MCP Server, a separate listing, marks its four Blob tools read-only or destructive (16 of 20). Official Python and JavaScript SDKs were checked on their registries, and the Python client retries by default. A REST call needs `x-ms-version`, `x-ms-date` and, for uploads, `x-ms-blob-type` (12 of 15).

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.

## 4. Reliability, 88 out of 100, up to 2.4 more on the total

Why it scored 88: Hosted reading. Azure status page with a history of post-incident reviews (20). The history lists three incidents in the last 90 days, West US network connectivity on 23 July 2026 (14:44 to 19:41 UTC), Azure OpenAI and Cognitive Services on 29 September, and gateway services in several regions from 30 September to 1 October. None names Storage. The page lists only broad incidents and the West US fault blocked traffic entering or leaving that region, so we count the record as minor (20 of 30). Targets published with numbers, 20,000 requests a second per standard account, 40,000 in 29 named regions, and 3,000 a second on one block blob (15). 503 Server Busy and 500 Operation Timeout are documented with advice to back off exponentially, the Python client retries three times by default, and `If-None-Match: *` makes a retried write safe. No Retry-After header was found in the pages read (13 of 15). The SLA document of 1 October 2026 commits to 99.9 per cent on the hot tier, 99.99 per cent for reads on RA-GRS accounts, with 10 and 25 per cent credits (10). Generally available (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.

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

Why it scored 85: A public OpenAPI 2.0 document for service version 2026-10-06 with 69 operations, each with a description (25). learn.microsoft.com/llms.txt returns 404, but every Learn page we asked for with `Accept: text/markdown` came back as Markdown, so half (5 of 10). Reference pages state each operation's purpose, permissions, limits by version and billing category, and seldom say when not to use one. Several are dated 2023 (15 of 20). The contract types 117 parameters, 15 with enums, but most inputs travel as headers or XML and metadata is free-form (12 of 15). Sample requests and responses on the reference pages, a table of 70-odd Blob error codes with HTTP status and message, and a 114-value error code enum in the contract. The contract carries no examples (13 of 15). Dated `x-ms-version` values, a versioning page updated 23 September 2026 with deployment by region, and a page of changes for each version (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.

## 6. Maintenance & community, 80 out of 100, up to 1.8 more on the total

Why it scored 80: Read as a closed service with official SDKs. azure-storage-blob 12.31.0 reached PyPI on 30 September 2026, and the versioning page was updated on 23 September (30). Four Python releases in the last 90 days, 12.30.1 on 27 August, 12.30.2 on 16 September, 12.30.3 on 22 September and 12.31.0 on 30 September (20). A versioning page and per-version change pages, Microsoft Q&A and the SDK issue trackers on GitHub, which we did not read (10 of 15). Official SDKs current in Python (12.31.0) and JavaScript (12.34.0) (15). The SDKs are released from the azure-sdk monorepos, CI not checked (5 of 10).

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.

## 7. Transparency & trust, 80 out of 100, up to 1.8 more on the total

Made of editorial 73, provenance 86.

Why it scored 80: Closed service under Microsoft's Product Terms, with MIT client libraries and a public API contract (15 of 30). The privacy statement, last updated September 2026, sends Azure customer data to the Product Terms and the Data Protection Addendum. The addendum of 22 May 2026 keeps customer data for 90 days after a subscription ends and deletes it within a further 90, and the redundancy docs say LRS replicates only inside the chosen region. These agree (26 of 30). The Modern Lifecycle Policy promises 12 months' notice before support ends, and the general-purpose v1 account retirement was announced in September 2025 for October 2026 (18 of 20). The addendum promises six months' notice of a new sub-processor, and data location follows the region and redundancy option chosen. The sub-processor list sits on the Service Trust Portal, a script-drawn page we could not read (14 of 20).

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 4 of the 7 things a reader expects, and has 2 clauses that cost points (3.4 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)

## 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.

- The lead was right on the interface and the docs. Its URL redirects to https://azure.microsoft.com/en-us/products/storage/blobs, and the contracting entity is Microsoft Corporation.
- unchecked: a free Blob Storage allowance. The free services page lists its services by script and the free account page names none for Blob Storage.
- unchecked: the internet egress (bandwidth) rate, which is a separate Azure meter and was not read.
- unchecked: whether Storage is on Azure's SOC 2 audit scope list. The scope page we loaded did not name services, and the reports sit on the Service Trust Portal.
- unchecked: the Microsoft sub-processor list. The Service Trust Portal page is drawn by script.
- unchecked: incidents limited to one region or to Storage alone, since the public status history lists only broad incidents.
- unchecked: MSRC advisories for Azure Storage in the last 12 months, and CI and open issues for the azure-sdk repositories.
- unchecked: the .NET, Java and Go client libraries, which were not looked up on their registries.
- Not established: whether 503 responses carry a Retry-After header, whether throttled or failed calls are billed, and whether new accounts have blob soft delete on by default.
- The specs repository has a stable folder named 2026-12-06 whose document still gives its version as 2026-10-06. The versioning page does not mention 2026-12-06.
- A judgement call. We took no deduction for SAS tokens in the URL query string, to match the Amazon S3 reading of presigned URLs. Microsoft's docs tell users to protect a SAS like an account key, so a stricter reading takes 10 off Security.
- The Product Terms page showed no effective date when read. Its competitive benchmarking clause is recorded as a fact with no deduction.

## Weaknesses

- Shared Key authorisation with the account's access keys is allowed until the owner sets `AllowSharedKeyAccess` to false
- Request logs are not collected until a diagnostic setting routes the StorageRead, StorageWrite and StorageDelete categories somewhere
- Requests and responses use headers and XML, and every authorised call must carry `x-ms-version`
- The pricing page draws its numbers by script, so an agent reading it sees no price. The Retail Prices API has them
- An Azure account needs a phone number and a credit or debit card, and no free Blob Storage allowance could be read

## 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.

- Request an Entra ID token for https://storage.azure.com/ and send it as a Bearer header with `x-ms-version` and `x-ms-date`. Put Blob also needs `x-ms-blob-type: BlockBlob`
- Ask for a Storage Blob Data role on the one container. Role changes can take up to 10 minutes to apply
- To share a file, call Get User Delegation Key, then sign a SAS with `sp=r`, `spr=https` and a short expiry. Treat the URL as a secret
- Send `If-None-Match: *` on Put Blob so a retry can't overwrite a blob another call wrote
- On 503 ServerBusy back off exponentially. After 500 OperationTimedOut check the blob's state before retrying, since the write may have succeeded

## 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.