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 aws/tools-for-devops-agent --skill investigation-cost-guardrailgit clone --depth 1 https://github.com/aws/tools-for-devops-agentWrote 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/aws/tools-for-devops-agent/investigation-cost-guardrail)<a href="https://agentmods.dev/skills/aws/tools-for-devops-agent/investigation-cost-guardrail"><img src="https://agentmods.dev/badge/skills/aws/tools-for-devops-agent/investigation-cost-guardrail/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/aws/tools-for-devops-agent/investigation-cost-guardrail"><img src="https://agentmods.dev/badge/skills/aws/tools-for-devops-agent/investigation-cost-guardrail.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00105 | $0.04575 |
| Opus 5 | $0.00053 | $0.02287 |
| Sonnet 5 | $0.00021 | $0.00915 |
| Haiku 4.5 | $0.00011 | $0.00458 |
Grade A, and why
investigation-cost-guardrail 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 5d 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 — 342 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Investigation Cost Guardrail Skill
Overview
This skill provides cost guardrails for ANY AWS service and ALL native agent tools — not just a hardcoded list. It uses heuristic classification to determine whether an API operation is free or paid, estimates cost before execution, and enforces per-investigation budgets.
Design Principle
Rather than listing every free/paid operation across 200+ AWS services, this skill uses three layers:
- Heuristic rules — classify any operation based on naming patterns and behavior
- Known-paid registry — explicit overrides for high-cost operations with pricing formulas
- Response validation — detect metered usage from API response fields after execution
Activation
This skill MUST be ALWAYS ACTIVE during investigations. It does NOT require user invocation.
Fetch Live Rate Before Estimating
The first time an operation is classified PAID by Layer 2, fetch the live rate before estimating cost.
For AWS operations: read references/pricing-reference.md for the exact Pricing API call patterns, filter fields, filter values, and failure handling. The reference file specifies — for each service and operation — whether to use Field:"operation" or Field:"usagetype", and the exact value to use. Do not derive these from the operation name.
For non-AWS tools (Splunk, Datadog, Grafana, etc.): use the cost model from Layer 0 directly — no live lookup available.
Layer 0: Native Agent Tool Classification
Before Layer 1 heuristics, classify the agent's own tools. These are NOT use_aws calls but have distinct billing implications:
Tool Cost Matrix
| Tool | Classification | Cost Model | Guardrail |
|---|---|---|---|
get_prometheus_metrics |
PAID | Billed per sample scanned — rate from live CW:PromQL:SamplesScanned usagetype lookup (AmazonCloudWatch, workload-region prefix) |
Track samples scanned per call; HALT if rate lookup returns 0 products |
use_aws |
VARIABLE | Depends on operation — apply Layers 1–3 | Full heuristic pipeline |
use_azure |
FREE | Azure Reader role, no per-call billing | Track count only |
grafana_query_prometheus |
CAUTION | Depends on Grafana data source billing model | Track count, warn at 50+ |
use_datadog |
CAUTION | Datadog API rate limits (no per-call $ cost, but may throttle) | Track count, warn at 100+ |
use_splunk |
PAID | Splunk search license (per GB ingested/searched) | Treat like CW Logs StartQuery |
use_pagerduty |
FREE | PagerDuty API (rate limited, not per-call billed) | Track count only |
shell |
CAUTION | May invoke aws, az, kubectl — untracked by Layers 1–3 |
Log commands, warn if aws/az detected |
subagent |
PAID | Counts toward agent-seconds billing ($0.0083/sec) | Track spawns, enforce total time |
fs_read, fs_write, fs_tree |
FREE | Local file I/O | No guardrail needed |
datetime |
FREE | Internal state ops | No guardrail needed |
write_scratchpad, read_scratchpad |
FREE | Internal state (may not be available in all environments) | No guardrail needed |
read_memories |
FREE | Internal memory recall | No guardrail needed |
What ships with it
8 files 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.
- 5d ago Changed · +22 lines 4e462111f01c
- 10d ago First seen · 320 lines · 105 tokens per session scan A 7c39fafd6fbd
investigation-cost-guardrail is a skill published in the GitHub repository aws/tools-for-devops-agent (46 stars, last pushed 5d ago), licensed Apache-2.0. It adds 105 tokens to every session and 4,575 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 2026-08-30.
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