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 lugassawan/swe-workbench --skill principle-cost-awarenessgit clone --depth 1 https://github.com/lugassawan/swe-workbenchWrote 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/lugassawan/swe-workbench/principle-cost-awareness)<a href="https://agentmods.dev/skills/lugassawan/swe-workbench/principle-cost-awareness"><img src="https://agentmods.dev/badge/skills/lugassawan/swe-workbench/principle-cost-awareness/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/lugassawan/swe-workbench/principle-cost-awareness"><img src="https://agentmods.dev/badge/skills/lugassawan/swe-workbench/principle-cost-awareness.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 | $0.00056 | $0.01592 |
| Opus 5 | $0.00028 | $0.00796 |
| Sonnet 5 | $0.00011 | $0.00318 |
| Haiku 4.5 | $0.00006 | $0.00159 |
Grade A, and why
principle-cost-awareness 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.
How it starts
The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Cost Awareness
Cost bugs are design bugs. They are cheapest to fix before the first dollar is spent. This skill teaches design-time discipline — choosing the right tier, topology, and access pattern — not post-billing cost reduction tactics.
FinOps Mindset
Cost is a feature requirement, not an afterthought. Treat budget the same way you treat latency and availability SLOs.
- Name a cost budget alongside the performance budget at design time. "Under $X/month at N req/s" is a testable acceptance criterion.
- Cloud bills are emergent: small per-request charges multiply by request volume, retention windows, and replica count in ways that are invisible in local testing.
- Assign cost ownership to the team that controls the resource. Shared cost pools obscure accountability and slow optimization.
- Unit economics clarify decisions: cost-per-request, cost-per-GB-stored, cost-per-active-user. Derive these early; revisit when scale changes by 10×.
Egress and Data Movement
Egress is the most common billing surprise — data that moves costs more than data that sits still.
- Intra-AZ traffic is typically free; cross-AZ traffic carries per-GB charges; cross-region is more expensive; egress out of a cloud to another cloud is most expensive (inbound/ingress is typically free on most providers). Map outbound data flows against this hierarchy at design time.
- Chatty microservice calls that exchange large payloads inflate egress costs non-linearly as request rates grow. Prefer coarse-grained APIs at zone boundaries.
- Naive replication — e.g., syncing every write to a second region — multiplies egress by replica count. Use asynchronous replication with tunable lag tolerance where strong consistency is not required.
- Read replicas in a different AZ or region pay egress on every read result. Profile read-result payload sizes before assuming replica reads are cheap.
- Cross-ref
principle-distributed-systems#Replication and Partitioningfor replication strategy semantics.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 7d ago First seen · 85 lines · 56 tokens per session scan A 962d581dbfde
principle-cost-awareness is a skill published in the GitHub repository lugassawan/swe-workbench (2 stars, last pushed 5d ago), licensed MIT. It adds 56 tokens to every session and 1,592 once invoked, about $0.0003 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 2026-09-03.
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