Borrowing it
Nothing to install: this file belongs to AcKeskin/contexture. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/AcKeskin/contexture/main/.github/instructions/codecs.instructions.mdgit clone --depth 1 https://github.com/AcKeskin/contextureWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/ackeskin/contexture/codecs)<a href="https://agentmods.dev/instructions/ackeskin/contexture/codecs"><img src="https://agentmods.dev/badge/instructions/ackeskin/contexture/codecs/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/ackeskin/contexture/codecs"><img src="https://agentmods.dev/badge/instructions/ackeskin/contexture/codecs.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01625 | $0.01625 |
| Opus 5.5 | $0.00650 | $0.00650 |
| Sonnet 5.5 | $0.00325 | $0.00325 |
| Haiku 4.5 | $0.00162 | $0.00162 |
Grade A, and why
contexture codecs.instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.
codecs rules
Auto-loaded by Copilot when editing files matching
**. Generated fromarchitectural-rules/codecs/— do not hand-edit.
Codec session lifetime
Treat each hardware encode/decode session as an explicitly-owned scarce resource with a defined create→use→destroy lifetime; release it deterministically, never on GC/finalizer timing. Hardware codec engines (NVENC/NVDEC, VideoToolbox, MediaCodec) expose a small fixed number of concurrent sessions; a leaked session starves every other consumer on the host until process exit. (VideoToolbox VTCompressionSession / VTDecompressionSession; NVENC nvEncOpenEncodeSessionEx + nvEncDestroyEncoder contract)
Open the session once for a stream and feed every frame through it; never create-and-destroy per frame. Session creation negotiates hardware, allocates the DPB/reference pool, and parses/builds parameter sets — per-frame churn destroys rate-control state, forces an IDR each time, and dominates latency. Reconfigure in place where the API allows (bitrate/framerate change) rather than tearing down. (NVENC reconfigure; VTSessionSetProperty; H.264/AVC §7.4.2 parameter-set continuity)
FLUSH/drain the codec before destroying the session and only then release. Encoders and decoders hold queued/in-flight frames (lookahead, B-frame reordering, async slots); destroying without draining silently drops trailing frames and truncates the bitstream. Submit the end-of-stream/flush sentinel, pump completions until the codec reports empty, then destroy. (VTCompressionSessionCompleteFrames; NVENC EOS NULL-input flush; MediaCodec end-of-stream BUFFER_FLAG_END_OF_STREAM)
For callback/async-completion codecs, treat submit and completion as separate events: do not assume output is ready when input returns, keep input frames/buffers alive until their completion fires, and join all outstanding completions before teardown. Releasing an input buffer or the session while a completion is pending corrupts output or faults the driver. (VTCompressionSession output handler; NVENC async event + nvEncLockBitstream; MediaCodec dequeueOutputBuffer)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 44 lines · 1,625 tokens per session scan A 68466c2729bb
contexture codecs.instructions.md is an instructions file published in the GitHub repository AcKeskin/contexture (2 stars, last pushed 2mo ago), licensed MIT. It adds 1,625 tokens to every session, about $0.0065 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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