overcast-event-bisect

overcast-event-bisect is a skill for Claude Code from kdr/overcast. It costs 43 tokens per session (646 once invoked), scanned A, original, Apache-2.0.

A video-analysis method for locating one irreversible change, such as a light turning on or a door opening. It narrows the time range by repeatedly checking the middle of the range, like a binary search.

In plain words
What is it for?
Use it when a video has a single monotonic transition and you need its exact timing. It is not suitable when the event happens more than once or switches back and forth.
Why use it?
Checking every video frame or making many visual checks is unnecessary when the condition changes only once and stays changed. The method reduces the number of checks needed to locate the transition.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the overcast plugin — 35 skills, 1 hook shipped together

Good fit Use it when a video has a single monotonic transition and you…

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Install with agentmods
npx agentmods add skills/kdr/overcast/overcast-event-bisect
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add kdr/overcast --skill overcast-event-bisect
Clone the repo
git clone --depth 1 https://github.com/kdr/overcast

Made for: Claude Code.

Or install overcast, the plugin that ships this one along with the rest of its 35 skills, 1 hook.

Wrote 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.

agentmods badge for overcast-event-bisect

README.md
[![agentmods](https://agentmods.dev/badge/skills/kdr/overcast/overcast-event-bisect.svg)](https://agentmods.dev/skills/kdr/overcast/overcast-event-bisect)
Your own site
<a href="https://agentmods.dev/skills/kdr/overcast/overcast-event-bisect"><img src="https://agentmods.dev/badge/skills/kdr/overcast/overcast-event-bisect.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 646 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00043 $0.00646
Opus 5 $0.00022 $0.00323
Sonnet 5 $0.00009 $0.00129
Haiku 4.5 $0.00004 $0.00065

Measured 7d ago against content hash 7ebe9835ac26, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

overcast-event-bisect 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 7d 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.

skills/overcast-event-bisect/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

overcast-event-bisect

Use this skill when a video contains a single MONOTONE transition — a condition that is false before some instant and true after it (or vice versa), and does not flip back. Binary search finds it in about log2(window/precision) vision calls (~12 calls localizes to ~1s inside an hour). Use the broad overcast skill and overcast/reference/verbs.md for exact flags.

Workflow

  1. Local clip + record id (see frame:// needs media on disk):
overcast doctor --json
overcast case init --json
overcast watch ./clip.mp4 --json        # -> record id REC (also gives shot context)
  1. Confirm the transition is bracketed AND monotone — the two endpoints must disagree on the predicate:
overcast see frame://REC@<lo> --prompt "Is <predicate> true? answer only yes or no" --json
overcast see frame://REC@<hi> --prompt "Is <predicate> true? answer only yes or no" --json

If both give the same answer, the flip isn't in [lo,hi]. If the predicate toggles more than once, it isn't monotone — use overcast-pinpoint instead.

  1. Bisect: test the midpoint, keep the half that still straddles the flip, repeat until hi - lo is within your precision:
overcast see frame://REC@<mid> --prompt "Is <predicate> true? answer only yes or no" --json
# keep the straddling half: if mid's answer == lo's answer, set lo=mid; else hi=mid
# (correct whichever way it flips — false->true OR true->false)
  1. Report the transition window and show it:
overcast note "<predicate> flips" --ref REC --at <lo-hi> --confidence high --json
overcast view REC --at <lo-hi> --json
overcast brief --export ./transition.md --json

Output

The converged [lo, hi] bracket — the two adjacent see frames that straddle the flip (their record.ids + media.at) — and the call count. That bracket IS the answer window — don't over-claim a single frame.

Caveats

Bisection is only valid for a one-way change; a light that blinks or a person who comes and goes will mislead it — verify monotonicity at step 2, and fall back to overcast-pinpoint (peak search) or overcast-presence-window for recurring or interval events. Needs the video local.

Read the full file on GitHub · 66 lines

Changes

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.

  1. 7d ago First seen · 66 lines · 43 tokens per session scan A 7ebe9835ac26

Subscribe to this mod's changes

overcast-event-bisect is a skill published in the GitHub repository kdr/overcast (16 stars, last pushed 3d ago), licensed Apache-2.0. It adds 43 tokens to every session and 646 once invoked, about $0.0002 per session on Opus 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 2026-08-30.