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.
npx skills add omar-y-abdi/furl-ctx --skill furlgit clone --depth 1 https://github.com/omar-y-abdi/furl-ctxWrote 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/skills/omar-y-abdi/furl-ctx/furl)<a href="https://agentmods.dev/skills/omar-y-abdi/furl-ctx/furl"><img src="https://agentmods.dev/badge/skills/omar-y-abdi/furl-ctx/furl/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/skills/omar-y-abdi/furl-ctx/furl"><img src="https://agentmods.dev/badge/skills/omar-y-abdi/furl-ctx/furl.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 | $0.00095 | $0.05872 |
| Opus 5 | $0.00048 | $0.02936 |
| Sonnet 5 | $0.00019 | $0.01174 |
| Haiku 4.5 | $0.00010 | $0.00587 |
Grade A, and why
furl 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 9d 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 — 293 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Furl — context compression for Claude Code and Codex
Furl reduces the tokens large tool outputs cost by compressing them, while keeping every dropped byte retrievable on demand. It ships these capabilities:
- An MCP server (
furl) exposing six tools in Claude Code and Codex. - A retrieval-aware skill in both hosts.
- Automatic hooks in Claude Code only. Codex uses explicit
furl_compresscalls; its separate package root intentionally excludes Claude's incompatible hooks.
Retrieval is pull-based, not push-based. The compressed text you read does not
contain the dropped rows. To inspect a specific dropped item, call furl_retrieve for
it by pattern, field, or line range. Retrieval is byte-exact for raw text. A JSON
array narrowed by select/fields comes back re-serialized — semantically complete
but pretty-printed, so not byte-identical to the source; when byte fidelity
matters (hashing, diffing, signature checks) pass raw: true on a row-select and
each matched row returns byte-identical to its source bytes, the rows rejoined with
fresh array punctuation, so each row is exact while the whole blob is not one
contiguous slice.
What actually decides byte-exactness is the offload route, not text-vs-JSON. Content the
router crushes structurally (columnar and tabular arrays) is stored as canonical json.dumps,
so a full furl_retrieve returns canonical bytes — byte-identical only when your input was
already canonical. Content offloaded whole-blob (plain text, or JSON too irregular to crush) is
stored verbatim and returns byte-exact. One consequence on the crush path: the hash keys the
canonical form, so two byte-different inputs that canonicalize the same collapse to one stored
entry — on the crush path the hash is a semantic identifier, on the whole-blob path a byte one.
Nothing is lost, but a one-off anomaly buried in otherwise-repetitive data will not appear in the compressed view unless you query for it. Trust a compressed summary for the shape of the data, not for surfacing an anomaly you were not already looking for.
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.
- 9d ago First seen · 293 lines · 95 tokens per session scan A 946818229045
furl is a skill published in the GitHub repository omar-y-abdi/furl-ctx (4 stars, last pushed 7d ago), licensed Apache-2.0. It adds 95 tokens to every session and 5,872 once invoked, about $0.0005 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 2026-08-31.
Other skills, from other repositories
sitrep
Situational awareness — where am I, what was I doing, what's next. Context recovery after compression, confusion, or mid-session reorientation.
alive:save
The human wants to checkpoint. Or: the stash has grown heavy — 5+ items, 30+ minutes, a natural pause in the work. The squirrel doesn't decide when to save. It surfaces the need and lets the human pull the trigger. Runs the full save protocol: confirms stash, writes log, updates state, generates projections…
alive:session-history
Revive sessions (quick or heavy), browse, and search — 'what happened recently?', 'find the session where we discussed X', 'revive yesterday's session'. For single-session recall and multi-session browsing. If the human needs to merge multiple sessions into one working context or detect conflicts between parallel…
alive:load-context
The human mentions a walnut to work on, asks about a specific venture/experiment/project, or wants to check status — not just explicit 'load X'. Load the brief pack (3 files), resolve the people involved, check the active bundle — then surface one observation and ask what to work on. Context loads in tiers: walnut and…
alive:mine-for-context
Deep context extraction from source material. Creates reference bundles, builds extraction plans, tracks what's been extracted, and discovers new targets — people, subjects, patterns, connections. The archaeologist that turns raw sources into structured knowledge. Can be invoked by alive:session-history for targeted…
alive:session-context-rebuild
Merge multiple sessions into one working context and detect conflicts between parallel sessions. Dispatches subagent swarm to read files touched, extract log history, and resolve contradictory state. Use when resuming after days away or when parallel sessions may have written conflicting decisions. For browsing or…