https://github.com/pioner92/symbolpeek-mcp

Ask for the symbol, not the file. Token-efficient MCP server giving AI coding agents symbol-level reads of TS/JS, Rust, Python, Java, Go, JSON, and Markdown
https://github.com/pioner92/symbolpeek-mcp

agent-mcp agents go java js llm mcp mcp-server puthon rust ts typescript

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Ask for the symbol, not the file. Token-efficient MCP server giving AI coding agents symbol-level reads of TS/JS, Rust, Python, Java, Go, JSON, and Markdown

• Host: GitHub
• URL: https://github.com/pioner92/symbolpeek-mcp
• Owner: pioner92
• License: mit
• Created: 2026-07-20T07:19:01.000Z (10 days ago)
• Default Branch: main
• Last Pushed: 2026-07-25T14:14:12.000Z (5 days ago)
• Last Synced: 2026-07-26T06:09:07.856Z (4 days ago)
• Topics: agent-mcp, agents, go, java, js, llm, mcp, mcp-server, puthon, rust, ts, typescript
• Language: Rust
• Homepage:
• Size: 1.06 MB
• Stars: 16
• Watchers: 0
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Security: SECURITY.md

Awesome Lists containing this project

README

          




### Semantic code intelligence for AI coding agents

Ask for the symbol you need—not the entire file.



  .ts  

  .tsx  

  .js  

  .jsx  

  .rs  

  .py  

  .java  

  .go  

  .json  

  .md





  

  





  Quick start ·

  Language support ·

  Tools ·

  Troubleshooting ·

  Tool reference





SymbolPeek is an MCP server that gives an AI coding agent a symbol-level view of

your codebase. Instead of reading a whole file to answer "what does this

function do" or "who calls it", the agent asks for one declaration and gets

exactly that.

TypeScript and JavaScript are analyzed with the official TypeScript Compiler

API. Rust, Python, Java, Go, JSON, and Markdown use embedded Tree-sitter for

syntax-level operations.

## Quick start

**Requirements**

- An MCP client. Any stdio MCP client works; [Codex and Claude

  Code](#connect-your-client) are documented below.

- **Node.js 20 or newer** — required for `.ts`, `.tsx`, `.js`, and `.jsx`

  analysis. Rust, Python, Java, Go, JSON, and Markdown work without it.

No clone, Rust toolchain, or manual build is required.

**macOS or Linux**

```sh

curl -fsSL https://raw.githubusercontent.com/pioner92/symbolpeek-mcp/main/scripts/install.sh | sh

```

**Windows PowerShell**

```powershell

irm https://raw.githubusercontent.com/pioner92/symbolpeek-mcp/main/scripts/install.ps1 | iex

```

The installer verifies the release checksum, installs the package, and then

**prints the exact command to connect your client**. It touches nothing outside

its own install directory — no client configuration is modified for you.

What the installer puts where

| Item | macOS / Linux | Windows |

| --- | --- | --- |

| Package (binary + bundled TypeScript runtime) | `~/.local/share/symbolpeek` | `%LOCALAPPDATA%\SymbolPeek` |

| `symbolpeek` and `sym` commands | linked into `~/.local/bin` | added to the user `PATH` |

| Lifetime statistics (created on first use) | `~/.config/symbolpeek/stats.json` (Linux)
`~/Library/Application Support/SymbolPeek/stats.json` (macOS) | `%APPDATA%\SymbolPeek\stats.json` |

That is the complete list. Connecting the MCP server and installing the

[optional agent guidance](#optional-agent-guidance) are separate, explicit

steps. See [Uninstall](#uninstall) to remove everything.

To inspect the installer before running it:

```sh

curl -fsSL https://raw.githubusercontent.com/pioner92/symbolpeek-mcp/main/scripts/install.sh -o install-symbolpeek.sh

less install-symbolpeek.sh

sh install-symbolpeek.sh

```

### Connect your client

The installer prints these commands with the correct absolute path already

filled in. Use the absolute path form — it works regardless of how your client

inherits `PATH`:

```sh

# Codex (macOS/Linux)

codex mcp add symbolpeek -- "$HOME/.local/share/symbolpeek/symbolpeek"

# Claude Code (macOS/Linux)

claude mcp add --transport stdio --scope user symbolpeek -- "$HOME/.local/share/symbolpeek/symbolpeek"

```

```powershell

# Codex (Windows)

codex mcp add symbolpeek -- "$env:LOCALAPPDATA\SymbolPeek\symbolpeek.exe"

# Claude Code (Windows)

claude mcp add --transport stdio --scope user symbolpeek -- "$env:LOCALAPPDATA\SymbolPeek\symbolpeek.exe"

```

Restart the client, then verify: `codex mcp list`, or `/mcp` inside Claude Code.

Use `--scope project` with Claude Code to enable the server for one project only.

### Optional: agent guidance

The tools work as soon as the server is connected. SymbolPeek also ships a

short [skill](skills/symbolpeek/SKILL.md) that tells the agent to *reach for*

those tools before opening whole files — without it the model calls them less

often.

Install it only for the clients you actually use:

```sh

symbolpeek install-skills codex     # writes ~/.codex/skills/symbolpeek

symbolpeek install-skills claude    # writes ~/.claude/skills/symbolpeek

symbolpeek install-skills all       # both

```

`CODEX_HOME` and `CLAUDE_CONFIG_DIR` override those locations. Restart the

client afterwards so it discovers the skill.

Try it with a prompt like:

```text

Use the symbolpeek MCP server. List the symbols in the absolute path

/project/src/dashboard.tsx, then read_symbol_context for Dashboard.

After that, find_references for useAuth and go_to_definition for one usage.

```

Configuration templates are checked in at

[`config/codex-mcp.toml.example`](config/codex-mcp.toml.example) and

[`config/claude-mcp.json.example`](config/claude-mcp.json.example).

## What you get

A real request against this repository's own TypeScript worker

(`src/language/typescript/worker.js`, 1,791 lines / 65 KB):

```text

read_symbol(path: ".../src/language/typescript/worker.js",

            symbol: "createProject.collectImports")

```

```json

{

  "symbol": "createProject.collectImports",

  "kind": "function",

  "file": ".../src/language/typescript/worker.js",

  "lines": { "start": 713, "end": 751 },

  "source": "function collectImports(fileName, collected, visited) {\n  ...\n}",

  "supported": true,

  "analysis": { "backend": "ts-compiler-api", "analysis_level": "syntax", "complete": true }

}

```

The agent receives **2.0 KB instead of 65 KB** — the 39 lines it asked for

rather than 1,791 lines it did not. Nested symbols are addressable by qualified

name, so the agent never has to read the enclosing function to reach the inner

one.

## Language support

Every language-aware operation, exactly as reported by `get_capabilities`:

| Operation | `.ts` `.tsx` `.js` `.jsx` | `.rs` | `.py` `.java` `.go` | `.json` | `.md` |

| --- | :---: | :---: | :---: | :---: | :---: |

| `read_symbol` | ✅ | ✅ | ✅ | ✅ | ✅ |

| `list_symbols` | ✅ | ✅ | ✅ | ✅ | ✅ |

| `search_symbols` | ✅ | ✅ | ✅ | ✅ | ✅ |

| `get_document_outline` | ✅ | ✅ | ✅ | ✅ | ✅ |

| `find_dependencies` | ✅ | ✅¹ | ✅¹ | — | — |

| `read_symbol_context` | ✅ | ✅¹ | ✅¹ | — | — |

| `find_implementations` | ✅ | ✅² | — | — | — |

| `find_references` | ✅ | — | — | — | — |

| `find_callers` | ✅ | — | — | — | — |

| `find_callees` | ✅ | — | — | — | — |

| `go_to_definition` | ✅ | — | — | — | — |

| `get_type` | ✅ | — | — | — | — |

| `get_diagnostics` | ✅ | — | — | — | — |

| `get_call_hierarchy` | ✅ | — | — | — | — |

| **Backend** | TypeScript Compiler API | Tree-sitter | Tree-sitter | Tree-sitter | Tree-sitter |

| **Analysis level** | semantic | syntax | syntax | syntax | syntax |

¹ Same-file only — conservative, no cross-file resolution.

² Explicit `impl Type` and `impl Trait for Type` blocks. Alias, re-export, and

blanket-impl resolution requires rust-analyzer and is not supported.

Unsupported operations fail with an explicit error rather than returning empty

results. `get_capabilities` returns this same matrix at runtime.

## Tools

### Navigation

| Tool | What it answers |

| --- | --- |

| `read_symbol` | "Show me the exact source for this symbol." |

| `list_symbols` | "What are the top-level symbols in this file?" |

| `search_symbols` | "Where is this symbol defined across the workspace?" |

| `go_to_definition` | "Where is the definition behind this usage?" |

| `read_symbol_context` | "Give me this symbol plus its minimal local context." |

### Code intelligence

| Tool | What it answers |

| --- | --- |

| `find_references` | "Where is this symbol referenced across the project?" |

| `find_callers` | "Which functions or methods call this symbol?" |

| `find_callees` | "Which named targets does this symbol call, including unresolved ones?" |

| `find_dependencies` | "Which local symbols does this symbol depend on?" |

| `get_call_hierarchy` | "What callers and callees surround this symbol?" |

### Type analysis

| Tool | What it answers |

| --- | --- |

| `get_type` | "What is the inferred type or signature at this location?" |

| `find_implementations` | "Which classes implement this interface or contract?" |

| `get_document_outline` | "What is the nested declaration structure of this file?" |

| `get_diagnostics` | "What TypeScript compiler diagnostics affect this file or symbol?" |

### Discovery and statistics

| Tool | What it answers |

| --- | --- |

| `get_statistics` | "How much source context has SymbolPeek avoided?" |

| `get_capabilities` | "Which operations does each language support?" |

Every request shape, option, and response format is documented in the

**[MCP tool reference](MCP_TOOLS.md)**.

## Where it helps (and where it doesn't)

SymbolPeek does not replace reading files or text search. It replaces the most

expensive pattern an agent hits on a real codebase: *find a symbol, find

everyone who touches it, and understand its type — across import aliases and

re-exports.*

**Where it genuinely saves an agent work and tokens**

- **One symbol out of a large file.** `read_symbol` / `read_symbol_context`

  return a single declaration instead of a whole file. On large files this is

  the bulk of the token saving.

- **Impact analysis without a grep loop.** `find_references` returns resolved

  locations, while `find_callers` also identifies the enclosing functions in

  one call. Both use the project's module resolution, including path aliases

  (`@app/...`) and barrel re-exports, which text search follows unreliably.

- **Resolved types.** `get_type` returns the instantiated signature (for

  example `useAsync`), which text search cannot produce.

- **Scoped discovery.** `search_symbols` finds declarations by name and kind

  (for example "hooks matching `conversation`") without the noise of string

  matches in comments and unrelated code.

**Where an agent should still use ordinary tools**

- Plain text, comments, small config files, or unsupported files — `grep` is faster.

- Understanding the full control flow inside one function — just read it.

- Very large monorepos — building a TypeScript program has real latency, so a

  targeted `grep` can win for a single lookup. Rust, Python, Java, Go, and JSON

  requests never start Node and stay fast regardless of project size.

**What makes the results trustworthy**

- Parsing, source ranges, type information, and cross-file navigation come from

  the TypeScript compiler and its AST. Semantic labels such as `hook` and

  `react_component` are conventions applied on top of that syntax tree, based on

  naming and JSX usage.

- Cross-file results are only as complete as module resolution allows: with a

  valid `tsconfig.json` they use its configured source set; without one they

  cover the target file and recursively resolved static imports, exports, and

  `require(...)` calls. Compiler options come from the project `tsconfig.json`.

- Rust, Python, Java, Go, and JSON source ranges and nesting come from

  Tree-sitter. Every result carries compact

  `analysis: { backend, analysis_level, complete }` trust metadata, where

  `complete: false` means the parser recovered from a syntax error.

## What gets indexed

**TypeScript and JavaScript** — function declarations, async functions,

generators, and arrow functions; exported and nested functions; React components

and hooks; classes and class methods; object methods; interfaces, type aliases,

enums and qualified enum members, variables, and constants.

Enum members are addressed by qualified name, for example

`Screens.PUBLISH_ACKNOWLEDGEMENT`. Symbol *names* are indexed; assigned string

values remain literals and require text search.

**Rust** — functions, structs, unions, enums and variants, traits, impl blocks

and methods, modules, constants, statics, type declarations, and macros. Impl

methods use qualified names such as `Client.send`, and trait impl methods use

`.send`.

**JSON** — object properties are indexed as RFC 6901 JSON Pointers, for example

`/checkout/errors/payment_failed`. Array-valued properties remain single

addressable branches instead of expanding every element, which keeps large

locale and data files token-efficient. `.jsonc` and JSON5 are not supported.

**Markdown** — headings are the symbols, nested by level, and a symbol spans the

whole section rather than the heading line. `read_symbol` with

`Quick start.Connect your client` returns that section alone; on this README

that is 839 bytes instead of 20 KB. Both `#` and underline (setext) headings are

indexed, `#` inside a fenced code block is not, and repeated headings such as

`Options` under several commands get `@line:column` selectors so each stays

addressable. Prose, lists, and code blocks are not indexed separately — this

finds sections, not full-text matches.

## Using the tools

Absolute file paths are the canonical, most reliable input. Relative paths first

use an explicit `SYMBOLPEEK_WORKSPACE_ROOT`, then filesystem roots supplied by a

compatible MCP client; multi-root workspaces resolve only when exactly one root

contains the requested path.

Supported files are parsed from their current contents on every request — there

is no index to rebuild and no stale cache to invalidate.

Unsupported extensions return `{ "supported": false }`. Missing files, parser

failures, and unknown symbols are returned as MCP invalid-parameter errors.

## How agents discover the tools

Two mechanisms nudge a model toward targeted reads:

- **Server instructions, always on.** Every MCP initialization response includes

  concise instructions to inspect outlines or search first, then retrieve only

  the required symbol. This works with any MCP client that exposes server

  instructions to its LLM — nothing to install.

- **The bundled skill, opt-in.** [`symbolpeek` skill](skills/symbolpeek/SKILL.md)

  is a stronger, always-loaded hint for Codex and Claude Code, with a trigger

  description covering code exploration and large JSON locale/configuration

  files. Install it with

  [`install-skills`](#optional-agent-guidance) if you want it.

No MCP server can force a client model to call a tool, but these mechanisms make

the intended workflow part of the model's default context. For another agent

that consumes neither, copy the short workflow from the bundled skill into that

client's global agent instructions.

## Statistics

The CLI reports lifetime context-avoidance statistics:

```sh

symbolpeek stats

symbolpeek stats --reset

```

`--reset` clears lifetime totals only. Session counters belong to the running

MCP process and are available through `get_statistics()`.

All numbers compare SymbolPeek with a counterfactual full-source baseline:

- **requests** — successful semantic calls;

- **files avoided** — distinct source files represented by each result, summed

  across calls (one `find_callers` request can count several files);

- **bytes / lines avoided** — full contents of those files minus a compact

  serialization of the semantic result;

- **estimated token savings** — avoided bytes at a fixed ~4 bytes/token

  heuristic;

- **average context reduction** — size-weighted across all requests.

Treat these as directional context-reduction estimates, not exact model-token

counts or billing data.

## Configuration

Prebuilt binaries detect their bundled TypeScript runtime automatically. These

variables are for advanced setups only:

| Variable | Purpose |

| --- | --- |

| `SYMBOLPEEK_WORKSPACE_ROOT` | Workspace root used to resolve relative source paths. |

| `SYMBOLPEEK_ALLOW_CWD_FALLBACK` | Allow relative paths to fall back to the process working directory (default `true`). |

| `SYMBOLPEEK_TYPESCRIPT_ROOT` | Directory containing the TypeScript runtime. |

| `SYMBOLPEEK_NODE` | Explicit Node.js executable for the parser worker. |

| `SYMBOLPEEK_STATS_PATH` | Override the lifetime statistics JSON path. |

For a global MCP installation, do **not** set `SYMBOLPEEK_WORKSPACE_ROOT` to a

fixed project — use absolute paths, or let the client provide filesystem roots.

Set `SYMBOLPEEK_ALLOW_CWD_FALLBACK=false` if relative paths must never resolve

against the server's working directory.

## Troubleshooting

**The client shows no SymbolPeek tools.**

Confirm registration with `codex mcp list` or `/mcp` in Claude Code, and restart

the client — MCP servers are discovered at startup. If registration itself

failed, re-run the `mcp add` command using the absolute binary path.

**TypeScript/JavaScript calls fail, other languages work.**

Node.js 20+ is missing or not visible to the server process. Check with

`node --version`; if Node is installed but not on the client's `PATH`, set

`SYMBOLPEEK_NODE` to the absolute Node executable.

**`symbolpeek: command not found` after installing on macOS/Linux.**

`~/.local/bin` is not on your `PATH`:

```sh

export PATH="$HOME/.local/bin:$PATH"   # add to your shell profile

```

The absolute path `~/.local/share/symbolpeek/symbolpeek` always works.

**Windows: the command is not recognized.**

The installer updates the user `PATH`; open a new terminal so the change is

picked up. If `irm ... | iex` is blocked, run

`Set-ExecutionPolicy -Scope Process RemoteSigned` first, or download the archive

manually.

**macOS blocks the binary.**

Release binaries are currently unsigned. If a browser-added quarantine flag

blocks a manually downloaded package, clear it:

```sh

xattr -dr com.apple.quarantine 

```

**A relative path resolves to the wrong project.**

Use absolute paths, or set `SYMBOLPEEK_WORKSPACE_ROOT` for a deliberately

project-scoped launch. `SYMBOLPEEK_ALLOW_CWD_FALLBACK=false` disables working

directory fallback entirely.

**An operation returns an unsupported-operation error.**

Check the [language support matrix](#language-support) — semantic operations are

TypeScript/JavaScript only.

Still stuck? [Open an issue](https://github.com/pioner92/symbolpeek-mcp/issues)

with your OS, client, SymbolPeek version (`symbolpeek --version`), and the failing

call.

## Uninstall

```sh

# macOS / Linux

rm -rf ~/.local/share/symbolpeek ~/.local/bin/symbolpeek ~/.local/bin/sym

rm -rf ~/.config/symbolpeek "$HOME/Library/Application Support/SymbolPeek"

```

```powershell

# Windows

Remove-Item -Recurse -Force "$env:LOCALAPPDATA\SymbolPeek", "$env:APPDATA\SymbolPeek"

```

Then remove the server from your client: `codex mcp remove symbolpeek` or

`claude mcp remove symbolpeek`. On Windows, also drop the SymbolPeek entry from

your user `PATH`.

If you installed the optional agent guidance, remove it too:

```sh

rm -rf ~/.codex/skills/symbolpeek ~/.claude/skills/symbolpeek

```

## Direct downloads

Prefer to install manually? Every package contains `symbolpeek`, the `sym`

alias, and the locked TypeScript runtime.

| Platform | Release package |

| --- | --- |

| Linux x86-64 | [Download](https://github.com/pioner92/symbolpeek-mcp/releases/latest/download/symbolpeek-x86_64-unknown-linux-gnu.tar.gz) |

| Linux ARM64 | [Download](https://github.com/pioner92/symbolpeek-mcp/releases/latest/download/symbolpeek-aarch64-unknown-linux-gnu.tar.gz) |

| macOS Apple Silicon | [Download](https://github.com/pioner92/symbolpeek-mcp/releases/latest/download/symbolpeek-aarch64-apple-darwin.tar.gz) |

| macOS Intel | [Download](https://github.com/pioner92/symbolpeek-mcp/releases/latest/download/symbolpeek-x86_64-apple-darwin.tar.gz) |

| Windows x86-64 | [Download](https://github.com/pioner92/symbolpeek-mcp/releases/latest/download/symbolpeek-x86_64-pc-windows-msvc.zip) |

Every package has a matching `.sha256` asset. All versions and release notes are

on the [GitHub Releases page](https://github.com/pioner92/symbolpeek-mcp/releases).

A manually extracted archive behaves exactly like an installer-placed one: run

the binary directly, register it with your client, and optionally run

[`install-skills`](#optional-agent-guidance).

SymbolPeek communicates over stdio when used as an MCP server. It normally does

not print a terminal interface; an MCP client starts it and exchanges JSON-RPC

messages through stdin/stdout.

## Documentation

| Document | Contents |

| --- | --- |

| [MCP_TOOLS.md](MCP_TOOLS.md) | Every tool's request shape, options, and response format |

| [ARCHITECTURE.md](ARCHITECTURE.md) | Internal design, provider boundary, request lifecycle |

| [CONTRIBUTING.md](CONTRIBUTING.md) | Reporting bugs, source builds, tests, releases |

| [CHANGELOG.md](CHANGELOG.md) | Release history |

| [SECURITY.md](SECURITY.md) | Reporting a vulnerability |

## Roadmap

The current foundation is intentionally focused. Natural next capabilities

include:

- symbol-level editing and replacement;

- deep type expansion beyond `get_type` hover signatures (fully resolved nested

  and generic types);

- JSX component trees and prop-flow analysis;

- project indexing and incremental parsing;

- additional language providers (Kotlin, Swift, C++).

## License

[MIT](LICENSE) © Alex Shumihin