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Insiders Features

Insiders Mode gives you access to experimental features in the GitHub MCP Server. These features may change, evolve, or be removed based on community feedback.

We created this mode to have a way to roll out experimental features and collect feedback. So if you are using Insiders, please don't hesitate to share your feedback with us!

Note

Features in Insiders Mode are experimental.

Enabling Insiders Mode

Method Remote Server Local Server
URL path Append /insiders to the URL N/A
Header X-MCP-Insiders: true N/A
CLI flag N/A --insiders
Environment variable N/A GITHUB_INSIDERS=true

For configuration examples, see the Server Configuration Guide.

MCP Apps

MCP Apps is an extension to the Model Context Protocol that enables servers to deliver interactive user interfaces to end users. Instead of returning plain text that the LLM must interpret and relay, tools can render forms, profiles, and dashboards right in the chat using MCP Apps.

This means you can interact with GitHub visually: fill out forms to create issues, see user profiles with avatars, open pull requests — all without leaving your agent chat.

Supported tools

The following tools have MCP Apps UIs:

Tool Description
get_me Displays your GitHub user profile with avatar, bio, and stats in a rich card
issue_write Opens an interactive form to create or update issues
create_pull_request Provides a full PR creation form to create a pull request (or a draft pull request)

Client requirements

MCP Apps requires a host that supports the MCP Apps extension. Currently tested and working with:

  • VS Code Insiders — enable via the chat.mcp.apps.enabled setting
  • Visual Studio Code — enable via the chat.mcp.apps.enabled setting

CSV output for list tools

CSV output mode returns supported list tool responses as CSV instead of JSON. This is intended to reduce response context for agents when scanning or summarising lists of GitHub data.

CSV output applies only to tools in default toolsets whose names start with list_, such as list_issues, list_pull_requests, list_commits, and list_branches. It does not add new tools or expose a tool argument for selecting the format; the server controls the response format through the Insiders feature flag.

Format

  • Nested objects are flattened into dot-notation columns, for example user.login, category.name, or head.ref.
  • Arrays are represented as compact single-cell values joined with ;.
  • body fields are whitespace-normalized so multiline Markdown does not expand a list response into many output lines.
  • Response metadata present in wrapped responses, such as pageInfo.* and totalCount, is emitted as #-prefixed lines before the CSV rows, followed by a blank line. Tools that return a root JSON array do not include metadata preamble lines.

Enabling CSV output

CSV output is enabled by Insiders Mode. For local development, it can also be enabled explicitly with the csv_output feature flag:

github-mcp-server stdio --features csv_output

Because this changes list tool response shape, clients that require JSON list responses should avoid enabling this feature.

How feature flags are resolved

Note

This section is for contributors. End users only need the table at the top of this page.

Insiders is a meta feature flag — the same shape as default or all for toolsets. It expands once at startup into a curated set of individual feature flags, and from that point on every code path keys off concrete flags, never InsidersMode directly. New experimental work should always get its own flag and then be added to the insiders expansion list, never folded into insiders as a catch-all.

Resolution order

  1. User input. Users may opt into specific features:
    • Local server: --features=<flag>,<flag> CLI flag (or GITHUB_FEATURES env var).
    • Self-hosted HTTP server: X-MCP-Features: <flag>,<flag> request header.
  2. Allowlist filter. User-supplied flags are filtered against AllowedFeatureFlags. Anything not on the allowlist is silently dropped — flags missing from the allowlist can only be turned on by remote-server feature management, not by end users.
  3. Insiders expansion. If insiders mode is on (--insiders, /insiders route, or X-MCP-Insiders: true), every flag in InsidersFeatureFlags is unioned in. The insiders expansion is not re-validated against the allowlist — insiders is a server-controlled switch that can reach internal-only flags.
  4. Server-side fallback (remote server only). Any flag not yet decided falls back to the remote server's feature manager, which can roll a feature out independently of user input or insiders membership.

AllowedFeatureFlags and InsidersFeatureFlags are deliberately independent sets:

  • A flag in AllowedFeatureFlags only is a regular opt-in: users can turn it on, but insiders does not auto-enable it. Granular issues/PRs flags work this way.
  • A flag in InsidersFeatureFlags only is reachable through insiders (and remote-server rollouts), but cannot be enabled by user input. Internal-only experiments work this way.
  • A flag in both is opt-in for end users and automatically on under insiders.

Adding a new feature flag

  1. Add a constant in pkg/github/feature_flags.go.
  2. Add it to AllowedFeatureFlags if end users should be able to opt in via --features / X-MCP-Features.
  3. Add it to InsidersFeatureFlags if insiders mode should turn it on automatically.
  4. Gate the behavior on the concrete flag (deps.IsFeatureEnabled(ctx, FeatureFlagX)), never on cfg.InsidersMode. There is a TestGitHubPackageDoesNotReadInsidersMode guard test that fails if pkg/github reads InsidersMode directly.
  5. The MCP-diff CI workflow picks up new entries in AllowedFeatureFlags automatically — see .github/workflows/mcp-diff.yml.