OpenCode Zen free models: verified input types

Which free models take an image?

Declared but not confirmed by this run: longcat-2.5-preview-free, minimax-m3.1-flash-free.

Why these numbers are trustworthy

Every opencode tool is enabled by default, so a model asked about an attachment will often answer correctly without perceiving it - by running bash and decoding the file itself. Observed directly: space-bunny-free cropped and zoomed a PNG with PIL and re-read its own output files; cat-jam-free ran ~20 bash commands (connected-component labelling, ink density, ASCII-art glyph rendering) and never said it could not see the image.

Two controls make a correct answer meaningful:

• each trial runs in its own empty temp directory holding exactly one attachment, so there is nothing to list, diff or read alongside it;
• the answer is a random 6-character code generated per run and rendered only as pixels - never as text, metadata or filename. The PDF embeds the code as a raster image XObject rather than text, so strings and pdftotext cannot recover it.

A cell is CONFIRMED only when the code came back correctly and no tool call appears in the transcript. With -r N the cell shows hits/N confirmed instead, which is the only way to separate capability from reliability. UNSCORABLE means the model used a tool, so the answer may have been computed from the file rather than perceived - it is neither a pass nor a fail. REFUSED is a model that said it cannot see the attachment: that is a real result, not a failure to answer. ERROR is a dead socket or an expired timeout - infrastructure, never evidence about the model.

Why pdf and video are not in this table

They used to be probed here and both columns were removed, because neither can be settled by asking a model:

• pdf is never delivered. The opencode client forwards an attachment as input_file only on /responses transports, and no free model is on /responses any more - they all use the provider-wide @ai-sdk/openai-compatible default. Any model that answered a pdf question correctly had run pdftoppm, which proves nothing about delivery.
• video is dropped before the request is built. Every model that "read" a video code had run ffmpeg and read the extracted frames.
• Both are machine-decodable by definition: any model with bash can rasterise or extract them, so a correct answer is not evidence of perception.

That question - does the client forward the attachment at all - is answered by capturing outgoing request bodies, not by prompting models. It was measured on 2026-10-13/17 and the conclusion is recorded in the clients next to this script.

pdf spot check (2026-10-18, manual, not a column)

Glm-5.3-flash-free is the only free model that declares pdf, so it was tried by hand with the same controls as this matrix - isolated dir, one attachment, and a code existing only as pixels:

pdf x3  probe.pdf   -> Error: Provider request failed with HTTP 500
png x1  probe.png   -> read correctly, no tools used

The png control is the point: same model, same minute, and the image came back clean, so the 500 tracks the pdf rather than the host. Two limits stay attached to it. The failure is an opaque 500 - the explicit content part type "file" is not supported message quoted in the clients did not reproduce, so read that message as historical. And a 500 cannot tell "unsupported" from "temporarily unavailable", so this establishes that delivery fails, not why. Converting first (pdftoppm -png) is unaffected, and is what the control row demonstrates.

The remaining unknown, audio, is untested: no TTS engine on this host means no way to place an unknown code into an audio stream.

Results

How to read this

• One trial per cell. A pass is evidence of capability, not of reliability. Nothing here predicts day-to-day accuracy.
• Capability != reliability. space-bunny-free can see images and still answer wrongly; the reliability section keeps the two apart.
• Declared != delivered. models.dev lists what a model claims to accept. The opencode client forwards image, and pdf only on /responses transports; video and audio have previously been observed dropped entirely.
• audio is untested - no TTS engine on this host, so an unknown code cannot be placed into an audio stream.
• jev-* is excluded: it is a /systemone typed-decision endpoint, not a chat transport.
• The model list is live - models.dev free (cost 0, not deprecated) intersected with /zen/v1/models, so it changes without a code edit.

Separate axis: reliability

No repeated image trials in this log. Re-run with -r 3 to get a reliability ratio per model.

Previous run of this method

Image probe, 2026-10-13, single trial, code known only as pixels:

space-bunny-free                   CONFIRMED
muse-spark-1.3-contributor-free    CONFIRMED  (deprecated since)
mimo-v2.6-flash-free               CONFIRMED
longcat-2.5-preview-free           CONFIRMED
step-5-preview-free                CONFIRMED  (deprecated since)
big-pickle                         no (declines)
cat-jam-free                       CHEATED (20 bash calls, pixel forensics; deprecated since)
ling-3.1-flash-free                no (declines; deprecated since)
nemotron-3.5-lightning-free        no (tried Read, then declined)

Four of those nine are now marked deprecated by models.dev and are no longer tested. beam-free, deepseek-v4.1-flash-free, glm-5.3-flash-free, nemotron-3-ultra-free and nemotron-3.5-super-vl-free did not exist in that catalogue; the model list is rebuilt from models.dev on every run, so they are covered by the table above instead of a hand-maintained list.

Reproduce

./mediamatrix.sh            # one image trial per free model, writes the HTML
./mediamatrix.sh -r 3 -a     # 3 more rounds per model, appended to the archive
./mediamatrix.sh -l          # free models + declared input media, runs nothing
./mediamatrix.sh -s          # re-score saved transcripts, call no model
./mediamatrix.sh -n          # re-render HTML from .mediamatrix-raw.tsv
./mediamatrix.sh -m 'a,b' -t 300   # restrict models, per-trial seconds

Per-cell hover shows the model's final answer. Raw log: .mediamatrix-raw.tsv, transcripts in .mediamatrix-logs/.