analyzing-api-call-traces

analyzing-api-call-traces is a skill for Claude Code, Codex from meltedinhex/analyst-ai-pack. It costs 75 tokens per session (635 once invoked), scanned A, original, Apache-2.0.

A guide for interpreting JSON logs of program calls collected by an isolated malware sandbox or API monitor. It groups low-level calls into behaviors such as file changes, networking, encryption, or process injection.

In plain words
What is it for?
Use it to classify API calls, detect ordered patterns such as remote process injection or self-deletion, rank findings, and map behaviors to MITRE ATT&CK techniques.
Why use it?
It turns a long event log into a higher-level explanation and highlights suspicious sequences. It uses an existing trace, so it does not run the sample to create one.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to classify API calls, detect ordered patterns such as remote process injection or self-deletion, rank findings, and map behaviors to MITRE ATT&CK techniques.

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Install with agentmods
npx agentmods add skills/meltedinhex/analyst-ai-pack/analyzing-api-call-traces
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 meltedinhex/analyst-ai-pack --skill analyzing-api-call-traces
Clone the repo
git clone --depth 1 https://github.com/meltedinhex/analyst-ai-pack

Made for: Claude Code, Codex.

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 analyzing-api-call-traces

README.md
[![agentmods](https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/analyzing-api-call-traces.svg)](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/analyzing-api-call-traces)
Your own site
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/analyzing-api-call-traces"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/analyzing-api-call-traces.svg" alt="Measured on agentmods" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 635 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 $0.00075 $0.00635
Opus 5 $0.00037 $0.00318
Sonnet 5 $0.00015 $0.00127
Haiku 4.5 $0.00007 $0.00064

Measured 8d ago against content hash 50efc21a97fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

analyzing-api-call-traces 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/analyst.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/analyzing-api-call-traces/SKILL.md · 84 lines

What it actually says

Analyzing API Call Traces

When to Use

  • You have a JSON API trace (CAPE/Cuckoo "apistats"/calls, API Monitor export) from a detonation.
  • You need to translate raw API calls into high-level behaviors and flag suspicious sequences (e.g., VirtualAllocExWriteProcessMemoryCreateRemoteThread).

Do not use this as a substitute for detonation — it consumes an existing trace produced in an isolated sandbox.

Prerequisites

  • A JSON API trace with at least an API name per call (and optionally arguments).

Safety & Handling

  • Consume traces only; never execute the sample to generate one outside a sandbox.

Workflow

Step 1: Group calls by category

python scripts/analyst.py classify trace.json

Buckets calls into process, memory, file, registry, network, crypto, and synchronization.

Step 2: Detect behavior signatures

Matches ordered API sequences that indicate techniques — remote injection, hollowing, self-deletion, dynamic API resolution (LoadLibrary/GetProcAddress bursts).

Step 3: Prioritize and report

Rank detected behaviors by severity and map each to ATT&CK.

Validation

  • Each API call is categorized; unknown APIs are reported, not dropped silently.
  • Injection-style sequences are detected only when the ordered prerequisites are present.
  • Detected behaviors map to ATT&CK techniques.

Pitfalls

  • Flagging individual benign APIs out of context — the sequence matters.
  • Assuming call order in the JSON equals execution order without a timestamp/index.
  • Ignoring failed calls (non-zero error) that never actually executed the behavior.

References

Files

What ships with it

3 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.

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. 8d ago First seen · 84 lines · 75 tokens per session scan A 50efc21a97fa

Subscribe to this mod's changes

analyzing-api-call-traces is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 75 tokens to every session and 635 once invoked, about $0.0004 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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