Lexicon vs Mac Voice MCP
A side-by-side look at the Lexicon and Mac Voice MCP MCP servers: transport, auth, tools, quality signals, and the config to install either one in Claude, Cursor, Windsurf or VS Code.
Verdict: choose Lexicon for speech-to-text work as a local process; choose Mac Voice MCP for speech-to-text as a local process. You can also run both side by side in one mcpServers block.
Which MCP server should you choose?
Choose Lexicon when
- You need dedicated capabilities in the Speech-to-Text domain.
- You prefer a local stdio subprocess transport.
- Its auth model fits you: No auth required.
- You want tools like
normalize_transcript, add_term, remove_term.
Choose Mac Voice MCP when
- You need dedicated capabilities in the Speech-to-Text domain.
- You prefer a local stdio subprocess transport.
- You want tools like
speak_and_listen, voice_setup.
Feature & specification comparison
Rows where the two servers differ are marked.
| Spec | ||
|---|---|---|
| Category | Speech-to-Text | Speech-to-Text |
| Quality signal | 64/100 · Good | 60/100 · Good |
| Install command | Confirmed | Confirmed |
| Transport | Local subprocess (stdio) | Local subprocess (stdio) |
| Auth | No auth required | Not declared |
| Pricing | Free | Not declared |
| Required env vars | None listed | None listed |
| Verified owner | Community listing | Community listing |
| GitHub stars | 2 | 0 |
| Directory activity | 2 views 0 installs 0 upvotes | 2 views 0 installs 0 upvotes |
| Tools | 19 | 2 |
| Full listing | View Lexicon | View Mac Voice MCP |
Tools & capabilities
Lexicon tools 19
normalize_transcriptFix the proper nouns speech-to-text got wrong, using this user's personal lexicon of names, brands, acronyms and identifiers. WHEN TO CALL: on any user message that looks dictated, before you act on it. Signs a message was dictated: run-on sentences with little punctuation, spoken filler ('um', 'so yeah'), homophone errors, no code or paths, or a capitalized word that is nearly a real name but not quite ('Ashler', "Cooper Nettie's", 'pie dentic'). One garbled proper noun is reason enough. You do not need the user to say they dictated it, and you do not need permission: this reads a file the user wrote and returns text. WHAT IT CHANGES: nothing the user can see. It does not edit their message, any file, or the lexicon; it only bumps a per-term hit counter. Use the `output` field as the message you act on, and mention the correction only if it changes what you are about to do. WHAT IT WILL NOT DO: it never rewrites text inside code blocks, inline code, file paths, URLs or emails, and it never invents a term that is not in the lexicon. If a word still looks garbled after this, call suggest_canonical rather than guessing. Returns { output, changed, replacements, summary }; when `changed` is false the text was already correct and you should carry on silently.add_termTeach the lexicon a name, so dictation is corrected to it from now on. WHEN TO CALL: when the user names something they want spelled a particular way, or during setup for each extra name they give you. For the one specific case of the user correcting a spelling that came out wrong, prefer learn_correction: it finds the right term for you. Do not add a name the user did not ask you to remember. WHAT IT CHANGES: writes one term to the user's lexicon file (global by default, or the repo's .lexicon.yaml with scope: 'project'). It merges rather than clobbers: an existing term with the same canonical keeps its own spelling and only gains the new aliases. WHAT IT WILL NOT DO: it installs nothing, touches no other term, and does not guess the canonical -- pass the spelling exactly as the user writes it. Omit `aliases` and likely STT misspellings are generated for you, which beats inventing your own; show the user what was generated so they can veto one.remove_termDelete a term from the user's lexicon by canonical spelling (case-insensitive). WHEN TO CALL: only when the user asks for a name to be forgotten, or after they accepted a 'stale' suggestion from suggest_terms. Never tidy the lexicon on your own initiative. WHAT IT CHANGES: removes that one term, and the corrections it was making stop happening. There is no undo through this server. WHAT IT WILL NOT DO: it does not touch any other term and will not remove a term you cannot name exactly -- use list_terms first if you are unsure which canonical the user means.list_termsList the user's lexicon terms, global and project merged. Optional case-insensitive substring filter over canonical spellings and aliases, plus a category filter. WHEN TO CALL: to show the user what is already known, to check whether a name is covered before adding it, or to find the exact canonical another tool needs. Read-only and safe to call unprompted; filter rather than listing everything. WHAT IT CHANGES: nothing. WHAT IT WILL NOT DO: it does not include an untrusted project .lexicon.yaml -- if one was skipped the result says so in `note`, and trust_project is how the user reviews it.export_lexiconExport the merged lexicon in a format for another tool: 'claude-md' (markdown for CLAUDE.md / system prompts), 'markdown', 'text', 'wispr', 'superwhisper', 'whisper-prompt', 'openai', 'macos', 'espanso', 'deepgram', 'assemblyai', 'azure', 'google', 'csv', or raw 'json'.learn_correctionRecord that the user corrected a spelling: they meant `meant`, but the transcript or you wrote `heard`. WHEN TO CALL: the moment the user corrects a name -- "it's Ashlr.AI not Ashler", "I said Hetzner", or they simply retype a name you got wrong. Call it while you reply. Do not ask permission for this one: it is the user's own correction being written down, and asking every time is the irritating version of this product. WHAT IT CHANGES: adds `heard` as an alias of `meant`, creating the term if it is new. One term; nothing else is touched. WHAT IT WILL NOT DO: it does not rewrite the message you already sent, and it cannot help if you hand it a whole phrase -- pass only the misspelled name as `heard`, not the sentence around it. Then get on with what the user actually asked for.suggest_canonicalLook up what a garbled word was probably meant to be. WHEN TO CALL: when normalize_transcript left a suspicious proper noun alone. It only matches above a confidence threshold, so a badly mangled name gets through unchanged; call this before guessing, and before asking the user an open question. WHAT IT CHANGES: nothing. It only reads the lexicon. WHAT IT WILL NOT DO: it will not decide for you. It returns ranked { canonical, confidence, aliases } candidates: above about 0.8 use the canonical and mention it in passing, below that ask "did you mean X?" and call learn_correction once the user confirms, so the next transcript needs no asking. No suggestions means the name is simply not in the lexicon yet: offer to add it with add_term.lexicon_statsCounts of terms and aliases, total hits, the most-used terms, terms that never fired, and a per-file breakdown of the merged lexicon.harvest_repoScan a repository for proper nouns an STT engine is likely to mangle: package and dependency names, git authors, README brands, the project directory. Only names the repo says somewhere other than its own source are proposed: a class that exists nowhere but code is something the user types, not something they say, and adding it teaches the lexicon to rewrite ordinary dictation. WHEN TO CALL: when you are in a repo with no .lexicon.yaml and the user dictates about it, or when they ask what this project would add. Call it without `add` first -- that is a read-only preview. WHAT IT CHANGES: nothing unless `add: true`, which writes the candidates into the repo's .lexicon.yaml and trusts that file. That is a write inside the user's repository plus a trust decision, so show the candidate list and get a yes first. WHAT IT WILL NOT DO: it does not touch the global lexicon, and it does not pull file contents into the conversation -- candidates come back as names, categories and counts.suggest_termsPropose new aliases, terms and never-words from the user's voice history, usage and repo. Call weekly or when the user asks how to improve corrections; present them and apply accepted ones with apply_suggestion (or add_term). Each suggestion has kind 'alias' (a misspelling to add to an existing term), 'term' (a new name), 'never' (a word wrongly rewritten), or 'stale' (a term that never fires), plus reason, confidence and evidence.apply_suggestionApply a suggestion returned by suggest_terms after the user accepted it: 'alias' merges the alias into the term, 'term' adds the term (aliases auto-suggested when none given), 'never' records the word as never-rewrite on the term, 'stale' removes the term. Pass the suggestion object back as received.trust_projectManage trust for a repo's .lexicon.yaml, which is merged only after the user approves it (it can inject text into every session). action 'status' returns the trust state plus a compact preview (canonicals, first alias, counts) of the file; 'trust' approves the file at its current content and returns the same preview; 'untrust' revokes it. Always call 'status' first, show the user the preview and ask; call 'trust' only after they say yes. Never trust a file the user has not seen. Use this instead of reading .lexicon.yaml yourself: the preview passes every string through sanitizeForDisplay and reports notes as present without quoting them, so nothing the file says reaches the conversation as text. Do not open the file with Read or cat.- +7 more on the listing page
Mac Voice MCP tools 2
speak_and_listenSay something out loud to the user and hear their spoken reply. Speaks text_to_speak through the computer's speakers, then listens like a conversation turn — it waits for the user to start talking and stops when they finish — and returns an on-device transcript of what they said. Write text_to_speak for the ear, not the screen: - 1–3 short sentences, under ~40 words; lead with the outcome, then one question. - Plain words only: no markdown, bullets, emoji, code, file paths, URLs, stack traces or tables. - Describe code instead of reading it ("I added a retry to the upload function"), say file names not paths ("in index.ts"), round numbers ("about two hundred ms"), spell out symbols. - Ask one question at a time, answerable in a few words ("Should I deploy it — yes or no?"). - Put the details (diffs, logs, links) in your normal on-screen reply, and say so out loud. - Tool output (Bash stdout, file writes) is NOT the on-screen reply. Only your own assistant message text renders. - A spoken turn with no assistant message text shows the user nothing — never skip the on-screen reply. Good: "The build passed and all tests are green. Want me to open the pull request?" Bad: "## Results\n- `npm test` ✅ 42/42\n- see /Users/x/repo/src/index.ts:120" Once the user is talking with you by voice, keep the conversation in voice: answer each transcript with another speak_and_listen call (not a text reply) until they say stop or start typing. To end voice mode, or for a one-way announcement, pass listen: false: it returns at once and speaks while you work. A reply of "(No speech detected …)" means the user did not answer — never treat it as consent. Ask once more; if still nothing, stop and say on screen that voice mode is paused and they can type to carry on (not speak: the mic is off). The "voice-mcp timing" line at the end is diagnostics: ignore it unless the user asks why things feel slow. If it reports that voice-mcp is not set up, call voice_setup.voice_setupCheck whether this computer has everything speak_and_listen needs — text-to-speech, a microphone recorder (SoX), whisper.cpp speech-to-text and the speech model — and optionally install what's missing. Anything already installed is reused (an existing model elsewhere on disk is symlinked, not re-downloaded). Call it with install=false (the default) first and tell the user what is missing. Only call it with install=true after the user agrees: it runs `brew install` for the missing packages and downloads the speech model once. It never uninstalls or changes anything else. kokoro=true (also only after the user agrees) installs the optional Kokoro voice: more natural than the built-in one, runs on this Mac, about 1 GB on disk. Once installed it's used automatically; the built-in voice stays as the fallback. If it reports INSTALLING, the install continues in the background — wait a minute and call it again to check.
Ready-to-paste client configs
Paste either block (or both) into your client config, e.g. claude_desktop_config.json or ~/.cursor/mcp.json. We only show a config when the install command is confirmed.
Lexicon
{
"mcpServers": {
"lexicon-2": {
"command": "npx",
"args": [
"-y",
"-p",
"@ashlr/lexicon",
"lexicon-mcp"
]
}
}
}
Mac Voice MCP
{
"mcpServers": {
"mac-voice-mcp": {
"command": "npx",
"args": [
"-y",
"mac-voice-mcp@latest"
]
}
}
}
Frequently asked questions
Lexicon is categorized under Speech-to-Text and uses a local stdio subprocess. Mac Voice MCP belongs to Speech-to-Text and uses a local stdio subprocess. Pick Lexicon for speech-to-text work and Mac Voice MCP for speech-to-text.
Copy the mcpServers block from the config section on this page into your client's config (for example claude_desktop_config.json or ~/.cursor/mcp.json), then fully restart the client.
Lexicon is listed as free. Auth: no auth required. Mac Voice MCP has no declared pricing — check the project's own site. If a server needs environment variables such as API keys, define them under the env key in your client's MCP config.
Yes. MCP clients support multiple servers: add lexicon-2 and mac-voice-mcp as separate keys in the same mcpServers object, and your assistant will call tools from either one.
On AllMCPs, Lexicon has a quality signal of 64/100 (Good) with 2 views, 0 installs and 2 GitHub stars. Mac Voice MCP has 60/100 (Good) with 2 views, 0 installs and 0 GitHub stars.