earshot

Ears for coding agents.

Watch the 22 s launch film - every sound in it was made in code by earshot forge; no recordings, no music track.

AI coding agents can now write the code that renders a film, a product demo or a game. They still cannot hear what they made. They cannot tell a premium key press from a cheap one, notice that a hit lands 80 ms after the cut, or hear that the music swells in the wrong place.

earshot turns sound into evidence an agent can reason about: what a file sounds like in words, how well it fits a description, the best moment inside a long recording, whether it is a real recording or code-synthesized, a second-by-second listening transcript of a whole film, an annotated picture of it, and a scorecard against professional launch films. It runs locally on CPU, as a CLI, a Python API and an MCP server.

With ears, an agent can also make its own sounds in code and improve them by listening (earshot forge, below).

$ earshot describe enter.ogg
  0.56 s short transient (attack 3 ms, decays in 190 ms). Sounds most like: a single mechanical keyboard key press
  (z +5.4), a soft key release click (z +3.6) ... [clear reading]. peak -0.1 dBFS, brightness 1.5 kHz ...

$ earshot match key.ogg "a deep thocky mechanical keyboard press" --alts "a clicky blue switch keyboard" "a mouse click"
  -> strong (z +3.7; would rank #2 among 322 vocabulary descriptions) ...

$ earshot find keys.ogg "a single mechanical key press" --top 4
  0:03.94-0:04.19 (0.24 s stroke, z +4.1 strong); 0:10.60-0:10.86 ...

$ earshot critique film.mp4
  VERDICT: close - 21 of 23 scored metrics in range ... FIX FIRST: 1. [major] nothing reaches body level until 0:01.01 ...

What it does

Every command prints a plain-language summary first; --json gives the full result, --out f.json saves it. Errors are one line on stderr (earshot <command>: error: ..., exit 1). Each CLI call is a new process and loads the models (~20-40 s) before it answers: for more than a few calls use the MCP server (models stay loaded) or one Python script with from earshot import api.

What an agent sees when it listens to that film with earshot sheet (frames, labelled sound events, spectrogram, loudness, sync to the beat):

Related MCP server: beatlyzer-mcp

Make sounds: earshot forge

Listening makes iteration possible. The agent writes a sound as code: a recipe of physical synthesis (modal resonators, contact excitations, filtered noise, a computed room and a microphone; no recorded audio inside). The forge renders candidates from the recipe's parameters, and a critic built from earshot scores each one: description match against named confusions, realness, closeness to real reference recordings, measured shape, and a model-free tonal-balance and tail check against the references. An evolutionary search keeps the best and mutates them. Then the agent reads the critic's words ("sounds like: a cork pop, a glass ting", "decay +2.4 outside the refs"), looks at spectrograms next to the references, rewrites the recipe, and runs it again.

earshot forge                                    # list the recipes: click, impact, keypress, pop, whoosh
earshot forge keypress --refs path/to/real/keypresses/ --budget 144 --reps 2 --tone 1.5 --keep 4 --robust 8 --dir made/keypress
earshot forge whoosh --target "a fast crisp air whoosh" --alts "a wind gust" "a sword swing" \
  --refs path/to/real/whooshes/ --tone 1.5 --dir made/whoosh

Output: the best diverse sounds as WAVs plus report.json with every candidate's parameters and scores, the same critic's scores of the real references (leave-one-out), held-out AudioSet tags, and with --robust N each pick re-rendered on N new seeds. Every score also carries model-free measurements (earshot/forge/tone.py): the 1/3-octave tonal balance against the references' median ("+16 dB at 500-630 Hz (above every ref)"), the tail and the length. In Python: from earshot.forge import forge.

Blind test. A key press, a UI click, a pop, a fast whoosh and an impact were made from scratch in code and played blind next to real recordings of the same kind of sound. The author picked the made one correctly 8 times out of 15: a coin flip. Only the made impact was spotted (its tail dies too fast). One listener and 15 trials is a small test, not a proof; it says the made sounds are no longer easy to tell from real ones.

Honest limits (Goodhart). The search optimises earshot's own models, and those can be pleased without the sound getting better. After a search the made sounds pass every model check, held-out ones included, so the model checks stop telling made from real; the 1/3-octave measurement still can. The realness model is easy to fool (a modal resonator plus a room and a noise floor reads "real"). Judge a made sound by the model-free measurements, spectrograms next to the references, robust re-renders, and a human blind test.

Install

Python 3.10+ and ffmpeg / ffprobe on PATH. CPU only; no GPU is used.

git clone https://github.com/Leonxlnx/earshot && cd earshot
python -m venv .venv
.venv/bin/python -m pip install torch --index-url https://download.pytorch.org/whl/cpu   # Windows: .venv/Scripts/python
.venv/bin/python -m pip install -e ".[mcp,llm,dev]"
.venv/bin/python -m earshot doctor --load

The first model use downloads two open models (~1.4 GB) into .cache/hf inside the repo (or EARSHOT_HOME): CLAP laion/larger_clap_general (text-audio embeddings) and the AudioSet tagger MIT/ast-finetuned-audioset-10-10-0.4593. After that earshot works offline.

Settings (environment variables): EARSHOT_THREADS (torch CPU threads, default min(4, cores/2)), EARSHOT_HOME (cache root), EARSHOT_PRECISION (bf16 by default, used only on CPUs with native bf16 such as AVX512-BF16 / AMX, fp32 everywhere else; fp32 forces fp32), EARSHOT_OFFLINE=1. earshot doctor --load reports what is in use.

MCP server for Claude Code

claude mcp add earshot --scope user -e EARSHOT_THREADS=3 -- /path/to/earshot/.venv/bin/python -m earshot mcp

Or in any client's .mcp.json:

{"mcpServers": {"earshot": {"command": "/path/to/earshot/.venv/bin/python", "args": ["-m", "earshot", "mcp"],
  "env": {"EARSHOT_THREADS": "3"}}}}

Models load on the first call and stay warm. On a slow machine start Claude Code with MCP_TIMEOUT=60000. The optional llm_critique tool reads GEMINI_API_KEY from the environment; never write a literal key into a file.

Python

import earshot
earshot.describe('whoosh.wav')
earshot.find('typing.ogg', 'a single isolated key press')
earshot.timeline('soundtrack.wav', video='film.mp4')
from earshot import api   # everything in one namespace: api.rank, api.critique, api.realness_many, ...

Agent skills

Two skills ship in skills/. Copy or symlink them into ~/.claude/skills/ (or a project's .claude/skills/).

• skills/earshot: how an agent should listen with earshot: which command answers which question, how to read the verdicts, when not to trust them.

• skills/real-sound: a full process for premium, realistic soundtracks for code-made films from real licensed recordings: sourcing with licence checks, a music edit, a JSON sound design, a deterministic mixer, measured QA, a multi-lens critique, mastering, credits and mux. earshot chooses, trims and verifies the sounds.

How good is it?

Every number below comes with the command that measured it in docs/VALIDATION.md. What earshot cannot judge is in docs/LIMITS.md.

• Matching descriptions (a held-out library of 125 real recordings, nothing tuned on it): in a library search a "strong" verdict is the right kind of sound 98% of the time and the exact variant 61% of the time.

• Finding the moment: on a recording of 17 single key presses the found trims land on real key presses; in a 300 s scene every planted event is found as a tight trim.

• Real vs code-synthesized: held-out ROC-AUC 0.92 with whole sound families held out. Firm verdicts call 6.7% of real clips synthesized and 5.5% of synthesized clips real; a fifth of clips get "uncertain".

• Listening through a soundtrack: 93% of the sound effects placed in a 60 s film mix are detected as events (89% of the quiet ones under music). A 60-90 s film takes about 1.5 minutes on a laptop CPU.

• Launch scorecard: each reference film critiqued against the other six falls in range on 86% of the metrics (the no-overfit baseline is about 71%; some rules changed after the first run, so it is not a blind test).

Limits

earshot hears through two open models and a set of measurements. Trustworthy: loudness, timing and sync to picture, "is this the kind of sound I asked for" on single exposed sounds, picking among candidates, obvious code-synthesized sources. Hints only: tags of events inside a busy mix, music genre and mood. It cannot judge taste or emotion, provenance or licences, speech content, or anything above 14 kHz from the models. The launch scorecard describes the style of the 7 films behind it, not every good film. Details in docs/LIMITS.md.

Repo map

earshot/            the package: CLI, Python API, MCP server, CPU model wrappers
  forge/            make sounds in code: DSP building blocks, critic, model-free tone checks, search, recipes/
  data/             vocabulary + calibration stats, realness model weights, launch profile (numbers only, no media)
skills/earshot/     agent skill: how to listen with earshot
skills/real-sound/  agent skill: real-recordings soundtracks (scripts, templates, prompts, references)
docs/               VALIDATION, LIMITS, launch-video sound playbook, integration notes, design notes
eval/               evaluation scripts and results per area (see eval/README.md)
tests/              pytest (fast by default; --slow loads the models)

No audio or video is stored in this repo. The evaluation data (licensed recordings and third-party films) is not redistributed; only derived numbers are committed.

Licence

MIT for the code (see LICENSE). The models are downloaded from their authors under their own licences: CLAP (laion/larger_clap_general) Apache-2.0, AST (MIT/ast-finetuned-audioset-10-10-0.4593) BSD-3-Clause. skills/real-sound/scripts/master.py is vendored from the Cinetic skill by the same author.