> ## Documentation Index
> Fetch the complete documentation index at: https://modelcontextprotocol.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Filesystems Charter

> Charter for the MCP Filesystems Working Group.

## Group Type

**Working Group**

## Mission Statement

The Filesystems Working Group exists to make MCP Resources bidirectional, so that an agent can write a result back to
the server it reads its inputs from. Agent platforms are converging on presenting services to models as filesystems, and
Resources already addresses content by URI under a [`file://` scheme the specification defines as identifying "resources
that behave like a filesystem"](/specification/draft/server/resources#common-uri-schemes). Currently, Resources carries
that surface in the read direction. The WG will produce a single Extensions Track SEP covering write operations,
optimistic concurrency control, and the interaction with change notification and caching.

## Scope

### In Scope

* **Specification Work**: One Extensions Track SEP, provisionally titled Filesystem Operations for Resources, covering:
  1. **Operations.** Define create, update, delete, and a metadata read (`stat`) that answers existence, size and
     last-modified for one URI without fetching the body.
  2. **Optimistic concurrency control.** Specify how two writers avoid a lost update, and how a client creates a
     resource under a create-if-absent precondition.
  3. **Change notification and caching.** Specify how a write interacts with `notifications/resources/updated`, the
     time-to-live and cache scope fields `ttlMs` and `cacheScope`, and the `lastModified` annotation.
* **Cross-Cutting Concerns**: Reconcile the proposals that extend this primitive into one coherent design.
  [SEP-2571, Resource Submission for Agent Coordination](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2571)
  proposes `resources/create` and `resources/delete`.
  [SEP-2532, Resource Streaming for Binary Content Delivery](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2532)
  proposes `resources/stream`.
  [SEP-1708, MCP Client-Brokered Filesystem Access](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1708)
  proposed a `files/*` method family standing beside Resources, and closed on 23 January 2026.
* **Documentation**: Document the new operations in the specification, and give server authors guidance on choosing
  between a resource write path and a tool-based one.

### Out of Scope

* A parallel `files/*` primitive standing beside Resources. The WG broadens the existing Resources primitive.
* Host-side sandbox and local-disk semantics. The WG standardizes the client and server wire format. How a host
  materializes resources into a filesystem for the model stays a host concern.
* Authorization policy for writes, beyond stating where the existing MCP authorization specification applies.

### Related Groups

* **File Uploads WG.** Both groups transfer content to a server. Coordination needed on where an upload-oriented flow
  ends and a resource write operation begins.
* **Skills Over MCP WG.** Filesystem dependency, including questions about write access, was an agenda item at the
  office hours of 24 March 2026 and remains open.
* **Agents WG.** Multi-agent and job orchestration systems are the motivating consumers of a shared write path.

## Leadership

| Role | Name            | Organization | GitHub                                               | Term    |
| ---- | --------------- | ------------ | ---------------------------------------------------- | ------- |
| Lead | Sambhav Kothari | Bloomberg    | [@sambhav](https://github.com/sambhav)               | Initial |
| Lead | Ola Hungerford  | Nordstrom    | [@olaservo](https://github.com/olaservo)             | Initial |
| Lead | Daniel Temesgen | Bloomberg    | [@DanielTemesgen](https://github.com/DanielTemesgen) | Initial |

## Authority & Decision Rights

| Decision Type                       | Authority Level                                        |
| ----------------------------------- | ------------------------------------------------------ |
| Meeting logistics & scheduling      | WG Leads (autonomous)                                  |
| Proposal prioritization within WG   | WG Leads (autonomous)                                  |
| SEP triage & closure (in scope)     | WG Leads (autonomous, with documented rationale)       |
| Technical design within scope       | WG consensus                                           |
| Spec changes (additive)             | WG consensus → Core Maintainer approval                |
| Spec changes (breaking/fundamental) | WG consensus → Core Maintainer approval + wider review |
| Scope expansion                     | Core Maintainer approval required                      |
| WG Member approval                  | WG Member sponsors                                     |

## Membership

| Name          | Organization | GitHub                                           | Discord | Level     |
| ------------- | ------------ | ------------------------------------------------ | ------- | --------- |
| Michael Cheah | Bloomberg    | [@michaelcheah](https://github.com/michaelcheah) |         | WG Member |

## Operations

| Meeting         | Frequency | Duration   | Purpose                               |
| --------------- | --------- | ---------- | ------------------------------------- |
| Working Session | Biweekly  | 60 minutes | Technical discussion, proposal review |

Discord: `#filesystems-wg`.

**Note** The cadence above is provisional. This is subject to change once the first working session sets it.

## Deliverables & Success Metrics

### Active Work Items

| Item                                     | Status   | Target Date | Champion |
| ---------------------------------------- | -------- | ----------- | -------- |
| SEP: Filesystem Operations for Resources | Ideating |             | TBD      |
| Take up SEP-2571 with its author         | Ideating |             | TBD      |

The group's first act is to take up SEP-2571 with its author, since it already covers create and delete.

### Success Criteria

* An accepted Extensions Track SEP covering create, update, delete and `stat`, with a defined optimistic concurrency
  control mechanism and a specified interaction with `notifications/resources/updated`, `ttlMs`, `cacheScope` and
  `lastModified`.
* Each proposal in this space resolved. SEP-2571 and SEP-2532 are open at time of writing, and each should end up folded
  in, superseded, or explicitly scoped out.
* Reference implementations in at least two Tier 1 SDKs.
* Two independent server implementations exercising the write path against a common client.

## Changelog

| Date       | Change          |
| ---------- | --------------- |
| 2026-08-24 | Initial charter |