---
title: Model Context Protocol (MCP) tool catalog
description: Complete technical reference of all 35 MCP tools exposed by exist.io for AI coding agents.
---

exist.io exposes **35 specialized tools** over the [Model Context Protocol](https://modelcontextprotocol.io) at `/mcp` (read-write) and `/mcp/readonly` (sandboxed read-only).

Every tool call uses standard JSON-RPC 2.0 with method `tools/call`.

---

## 1. Repository & Git Navigation (11 tools)

| Tool Name | Scope | Parameters | Description |
| :--- | :--- | :--- | :--- |
| `repo_get` | Read | `owner` (string), `repo` (string) | Retrieve repository details, default branch, and visibility. |
| `repo_list` | Read | `owner` (string), `limit` (int, opt) | List repositories within a namespace. |
| `repo_tree` | Read | `owner` (string), `repo` (string), `ref` (string, opt), `recursive` (bool, opt) | Recursively inspect file trees at a specified commit, branch, or tag. |
| `file_read` | Read | `owner` (string), `repo` (string), `path` (string), `ref` (string, opt) | Read the content, encoding, and byte size of a file blob. |
| `search_symbols` | Read | `ownerSlug`, `repoName`, `query`, `ref` (opt), `kind` (opt), `limit` (opt) | Pure-Go AST semantic symbol search (functions, structs, classes, interfaces). |
| `commit_get` | Read | `owner` (string), `repo` (string), `sha` (string) | Get commit metadata, author, committer, and parent hashes. |
| `commit_list` | Read | `owner` (string), `repo` (string), `ref` (string, opt), `limit` (int, opt) | List commits reachable from a reference. |
| `branch_list` | Read | `owner` (string), `repo` (string) | List all branches in the repository with target commit SHAs. |
| `diff_compare`| Read | `owner` (string), `repo` (string), `base` (string), `head` (string) | Compute two-way and three-way diffs between two refs or commits. |
| `tag_list` | Read | `owner` (string), `repo` (string) | List all tags in the repository. |
| `ref_resolve` | Read | `owner` (string), `repo` (string), `ref` (string) | Resolve symbolic ref (such as `HEAD` or branch name) to an exact SHA. |

---

## 2. Pull Request Management (8 tools)

| Tool Name | Scope | Parameters | Description |
| :--- | :--- | :--- | :--- |
| `pull_request_create` | Write | `owner`, `repo`, `title`, `base`, `head`, `body` (opt) | Open a new pull request between `head` and `base` branches. |
| `pull_request_get` | Read | `owner`, `repo`, `number` (int) | Retrieve pull request details, state, and mergeability verdict. |
| `pull_request_list` | Read | `owner`, `repo`, `state` (string, opt: `open`\|`closed`\|`all`) | List pull requests for a repository. |
| `pull_request_update` | Write | `owner`, `repo`, `number`, `title` (opt), `body` (opt) | Update pull request title or description. |
| `pull_request_merge` | Write | `owner`, `repo`, `number`, `method` (string: `merge`\|`squash`), `commit_message` (opt) | Merge a pull request through policy rulesets. |
| `pull_request_close` | Write | `owner`, `repo`, `number` | Close an open pull request without merging. |
| `pull_request_files` | Read | `owner`, `repo`, `number` | List all modified, added, and deleted files in a pull request. |
| `pull_request_diff` | Read | `owner`, `repo`, `number` | Retrieve the unified diff patch for a pull request. |

---

## 3. Reviews, Threads & Collaboration (8 tools)

| Tool Name | Scope | Parameters | Description |
| :--- | :--- | :--- | :--- |
| `thread_create` | Write | `owner`, `repo`, `pull_number`, `body`, `path` (opt), `line` (opt) | Start a line-level review thread or top-level PR discussion. |
| `thread_reply` | Write | `owner`, `repo`, `pull_number`, `thread_id`, `body` | Reply to an existing review thread. |
| `thread_list` | Read | `owner`, `repo`, `pull_number` | List all review threads and comments on a pull request. |
| `thread_resolve` | Write | `owner`, `repo`, `pull_number`, `thread_id`, `resolved` (bool) | Mark a review thread as resolved or reopen it. |
| `reaction_add` | Write | `owner`, `repo`, `comment_id`, `content` (string: `+1`, `-1`, `heart`, etc.) | Add an emoji reaction to a comment. |
| `reaction_list` | Read | `owner`, `repo`, `comment_id` | List all emoji reactions on a comment. |
| `label_list` | Read | `owner`, `repo` | List all labels defined in the repository. |
| `label_apply` | Write | `owner`, `repo`, `pull_number`, `labels` (array of strings) | Apply labels to a pull request. |

---

## 4. Status Checks & Rulesets (8 tools)

| Tool Name | Scope | Parameters | Description |
| :--- | :--- | :--- | :--- |
| `check_suite_create` | Write | `owner`, `repo`, `head_sha` | Create a new check suite for a commit. |
| `check_run_create` | Write | `owner`, `repo`, `head_sha`, `name`, `status` (string), `conclusion` (opt) | Register a check run (e.g. `test/unit`, `lint/vet`). |
| `check_run_update` | Write | `owner`, `repo`, `check_run_id`, `status`, `conclusion`, `output` (opt) | Update check run state and output. |
| `status_check_report` | Write | `owner`, `repo`, `head_sha`, `context`, `state` (string: `pending`\|`success`\|`failure`) | Convenience tool to report a status check outcome. |
| `ruleset_list` | Read | `owner`, `repo` | List all active rulesets applicable to a repository. |
| `ruleset_get` | Read | `owner`, `repo`, `ruleset_id` | Get details and conditions for a specific ruleset. |
| `ruleset_evaluate` | Read | `owner`, `repo`, `ref` | Test ruleset policy rules against a specific branch ref. |
| `merge_blockers_list` | Read | `owner`, `repo`, `pull_number` | Inspect active blockers (missing approvals, failing checks) preventing a PR from merging. |

---

## Read-Only Sandbox Policy

When connecting to `http://<host>:<port>/mcp/readonly`:
- All **Read** tools operate normally.
- All **Write** tools immediately return error code `-32001` (Unauthorized) with message:
  ```json
  {
    "jsonrpc": "2.0",
    "id": 1,
    "error": {
      "code": -32001,
      "message": "Tool '<tool_name>' is not permitted on read-only MCP endpoint"
    }
  }
  ```