Compiler Explorer
REMOTE · GODBOLT.ORG
Compile code with thousands of compilers, inspect the assembly, and share godbolt.org links
Available components
Last scanned (13 hours ago)
Scores higher than 91% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Developer Tools
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security74
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Nothing on it is marked destructive, but we can't show that an anonymous caller can only read: full credit needs the server to list at least one tool and every tool to be verifiably read-only. We use a best-effort check of tool names and descriptions to tell read-only tools from tools that change things, so some genuinely read-only tools may not get full credit. Names that start with a read verb (get, list, read, search and similar) and accurate readOnlyHint annotations help. Meet that to earn full credit, or require authorisation. See how to fix → View diagnostics → Partial
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability73
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1081 tokens (~154/item across 7 items; 7 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 7 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 7 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Checks we ran (13)
- TLS certificate
- Authorization
- HTTPS
- HSTS header
- DNSSEC
- Transport
- Schema quality
- Stability
- Tool coverage
- Injection markers
- Destructive annotations
- Judged manipulation
- MCP protocol
Does not apply to this hosted endpoint (2)
- Supply Chain SecurityScored on package channels only. This is a hosted endpoint, so there is nothing to install or inspect.
- Provenance & TransparencyScored on package channels only. This is a hosted endpoint, so there is nothing to install or inspect.
The score does not measure everything. What the score does not measure →
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 4 Nov 26 0
- Server version: gh-20172 → gh-20192 functional
- 3 Nov 26 0
- Server version: gh-19988 → gh-20172 functional
- 29 Oct 26 0
- Server version: gh-19942 → gh-19988 functional
- 28 Oct 26 0
- Server version: gh-19934 → gh-19942 functional
- 27 Oct 26 0
- Server version: gh-19828 → gh-19934 functional
- 25 Oct 26 0
- Server version: gh-19727 → gh-19828 functional
- 20 Oct 26 0
- Server version: gh-19707 → gh-19727 functional
- 19 Oct 26 0
- Server version: gh-19618 → gh-19707 functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Probed https://godbolt.org/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=godbolt.org | CN=Amazon RSA 2048 M04,O=Amazon,C=US | 23 Jun 2026 | 6 Jan 2027 | RSA 2048 | SHA256-RSA | 49c41206ff97537c9e6d5d263f83d0d |
| SANs: godbolt.org, *.godbo.lt, *.compiler-explorer.com, godbo.lt, compiler-explorer.com, *.godbolt.org | ||||||
| CN=Amazon RSA 2048 M04,O=Amazon,C=US (CA) | CN=Amazon Root CA 1,O=Amazon,C=US | 23 Aug 2022 | 23 Aug 2030 | RSA 2048 | SHA256-RSA | 773124f2a952e3ed18a58bdb85d1bc0ce5f27 |
| CN=Amazon Root CA 1,O=Amazon,C=US (CA) | CN=Starfield Services Root Certificate Authority - G2,O=Starfield Technologies\, Inc.,L=Scottsdale,ST=Arizona,C=US | 25 May 2015 | 31 Dec 2037 | RSA 2048 | SHA256-RSA | 67f944a2a27cdf3fac2ae2b01f908eeb9c4c6 |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of godbolt.org. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | Trust anchor | 20326, 38696 | 8, 8 | Verified |
| org. | DS published | 725, 26974 | 8, 8 | Verified |
| godbolt.org. | No DS | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://godbolt.org/mcp | Verified | 200 | |
| http (plaintext) | http://godbolt.org/mcp | HTTPS enforced | 301 | https://godbolt.org/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
compile ~257
Compile source code and return assembly output, stdout, and stderr
| Name | Type | Req | Description |
|---|---|---|---|
| compiler | string | – | Compiler ID from list_compilers (e.g. "g161"). If omitted, uses the language's `defaultCompiler` from list_languages. |
| execute | boolean | – | Run the program instead of returning assembly. `asm` becomes empty; runtime output goes to top-level `stdout`/`stderr`; compile diagnostics move to `buildResult.stdout`/`stderr`. |
| filters | object | – | Output filters |
| language | string | yes | Language ID (e.g. "c++", "c", "rust", "python") |
| libraries | array | – | Libraries to link. |
| maxAsmLines | integer | – | Cap asm output (default 500 lines). |
| maxStderrLines | integer | – | Cap each stderr stream — compile and execute separately (default 100). |
| maxStdoutLines | integer | – | Cap each stdout stream — compile and execute separately (default 100). |
| options | string | – | Compiler flags (e.g. "-O2 -std=c++20 -Wall") |
| source | string | yes | Source code to compile |
| stdin | string | – | Standard input for execution (requires execute=true) |
No output schema declared.
No examples provided.
generate_short_url ~109
Create a Compiler Explorer short URL for sharing code with compiler settings
| Name | Type | Req | Description |
|---|---|---|---|
| compiler | string | yes | Compiler ID from list_compilers (e.g. "g161", "clang_trunk") |
| language | string | yes | Language ID (e.g. "c++", "c", "rust") |
| libraries | array | – | Libraries to include. |
| options | string | – | Compiler flags (e.g. "-O2 -std=c++20") |
| source | string | yes | Source code |
No output schema declared.
No examples provided.
get_shortlink_info ~120
Retrieve source and compiler config from a CE short URL. Compiler entries are returned in the `compile` tool's shape ({compiler, options, libraries:[{id, version}]}). Multi-pane shortlinks (executors, conformance views, CMake trees, per-compiler filters/tools) are flattened — only the basic compile inputs survive.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Short link ID or full URL (e.g. "G38YP7eW4" or "https://godbolt.org/z/G38YP7eW4") |
No output schema declared.
No examples provided.
list_compilers ~355
List available compilers, optionally filtered by language
| Name | Type | Req | Description |
|---|---|---|---|
| includeExperimental | boolean | – | With `latestPerMajor: true`, also include experimental compilers (c++ proposal forks, llvm-mos platform variants). Off by default — bloats "newest X" answers. |
| instructionSet | string | – | Target architecture filter. Combine with `latestPerMajor: true` for "newest X for arch Y" (e.g. `{language:"c++", instructionSet:"amd64", latestPerMajor:true}`). |
| language | string | – | Language ID to filter by (e.g. "c++", "rust", "python") |
| latestPerMajor | boolean | – | "Newest X" filter. By release track (stable/nightly/prerelease/experimental): newest stable per (language, instructionSet, semver major); all nightly + prerelease; experimental skipped unless `includ… |
| lean | boolean | – | Force id+name only, regardless of count. Useful to browse the catalog before drilling in. |
| match | string | – | Case-insensitive AND-of-tokens filter on id and name. Punctuation splits tokens; numeric tokens match whole-word ("gcc 14.1" matches "14.1.0" not "14.10"); alphanumeric tokens substring-match ("g14"… |
| maxResults | integer | – | Cap full-detail entries (default 25). Beyond the cap, degrades to lean (id+name only) with a refinement hint. |
No output schema declared.
No examples provided.
list_languages ~24
List supported languages. Each entry has `defaultCompiler` and `compilerCount`.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
list_libraries ~152
List available libraries for a given programming language
| Name | Type | Req | Description |
|---|---|---|---|
| language | string | yes | Language ID (e.g. "c++", "rust") |
| lean | boolean | – | Force id+name only, regardless of count. Useful to browse the catalog before drilling in. |
| match | string | – | Case-insensitive AND-of-tokens filter on id, name, and version strings (so "boost 1.88" finds Boost when one of its versions matches 1.88.x). Numeric tokens match version-prefix; alphanumeric substri… |
| maxResults | integer | – | Cap full-detail entries (default 25). Beyond the cap, degrades to lean (id+name only) with a refinement hint. |
No output schema declared.
No examples provided.
lookup_asm_instruction ~64
Look up documentation for an assembly instruction
| Name | Type | Req | Description |
|---|---|---|---|
| instruction_set | string | yes | Instruction set architecture (no default — must match the asm dialect being looked up). |
| opcode | string | yes | Assembly instruction mnemonic (e.g. "MOV", "ADD", "JMP") |
No output schema declared.
No examples provided.
How do I install the Compiler Explorer MCP server?
Compiler Explorer is a hosted endpoint at https://godbolt.org/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · godbolt.org
claude mcp add --transport http compiler-explorer-compiler-explorer 'https://godbolt.org/mcp'
What is the Compiler Explorer MCP server?
Compiler Explorer is an MCP server listed in the public MCP registry as io.github.compiler-explorer/compiler-explorer. Compile code with thousands of compilers, inspect the assembly, and share godbolt.org links. This page covers its hosted endpoint (https://godbolt.org/mcp).
Is the Compiler Explorer MCP server safe to use?
Compiler Explorer scores 85 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Compiler Explorer MCP server expose?
Compiler Explorer exposes 7 tools: compile, list_compilers, list_languages, list_libraries, lookup_asm_instruction, and 2 more. Their descriptions and schemas cost roughly 1,081 tokens of context every time the server is loaded.
Does the Compiler Explorer MCP server require authentication?
No. We connected to Compiler Explorer without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Compiler Explorer MCP server still maintained?
Compiler Explorer is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What did VerifyMCP test on the Compiler Explorer MCP server?
VerifyMCP ran 13 checks on Compiler Explorer, covering TLS certificate, Authorization, HTTPS, HSTS header and 9 more. Supply Chain Security and Provenance & Transparency do not apply to a hosted endpoint, so they were not tested. The score does not measure everything, and the scoring documentation lists what it leaves out.