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Overview

Provider tools are callable actions Stella, your AI teammate, gains from a connected provider. Unlike MCP Connections (which expose read-only tools from external servers) provider tools are built into Custral and can take actions (for example, create a GitHub issue) using your workspace’s existing connection. Any tool that writes or deletes asks for your approval before it runs. They appear under Settings → AI → Rules & Skills → Provider Tools, and light up automatically while the matching provider is connected.

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How it works

  • A provider tool is available only while that provider is connected for your workspace. Disconnect the provider and its tools disappear instantly.
  • Each tool has a risk: read tools run on their own; write and destructive tools pause and ask you to approve the action first (the same permission card Stella uses for any change).
  • Tools are named plainly (e.g. github_create_issue) so Stella (and your skills) can reference them.
  • Provider tools count toward Stella’s tool budget alongside base tools and MCP tools.

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Turning a tool off

Each tool has an Enabled toggle. Turn it off to stop Stella from using that specific tool while keeping the provider connected. Useful when you want, say, GitHub reads but not the ability to create issues. A disabled tool is never offered to Stella (and won’t run even if a skill lists it) until you turn it back on. The toggle is workspace-wide and only admins can change it.

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Scoping a skill to specific tools

When you author a Skill (Settings → AI → Rules & Skills → Skills), the Allowed tools picker lets you restrict that skill to a chosen set of tools, base or provider. Leave it empty for full access. A /create-issue skill, for instance, can be limited to just github_create_issue so it stays focused.

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Using it

  1. Connect the provider (e.g. GitHub) under Settings → Connections.
  2. Open Settings → AI → Rules & Skills → Provider Tools to see the tools it contributes, with their provider and risk.
  3. Ask Stella to use one, e.g. “file a GitHub issue in custral/app titled ‘Fix login redirect’”.
  4. For a write tool, approve the action when Stella asks. Read tools return results directly.

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Troubleshooting

  • Stella says a provider is “not connected.” The provider isn’t connected (or was disconnected). Reconnect it under Settings → Connections, then retry.
  • A write tool didn’t run. Write and destructive tools require your approval, look for the approval prompt and confirm it. In Ask permission mode every gated tool asks first.
  • A provider tool isn’t listed. It only appears while the provider is connected. Confirm the connection is active.
  • Stella won’t use a tool that’s connected. Check its Enabled toggle on this tab. A tool turned off here is withheld from Stella even when the provider is connected and even if a skill lists it. Toggle it back on.
  • A skill can’t use a tool. If the skill has Allowed tools set, only those tools are available while it runs. Add the tool to the skill’s allowed list, or clear the list for full access.
  • The tool reports an error (e.g. github_repo_invalid). Check the arguments. Repositories are owner/repo. Stella surfaces the provider’s error so you can correct and retry.