CC steam-community-inventory
Retrieves Steam inventory data and manages trade offers on steamcommunity.com
As a process C 55/100 · Has gaps — weak spots: when it triggers, inputs and preconditions, consistency
What is at stake
Medium-severity findings: the skill is probably honest, but read what alarmed the scanner.
Below is the worst case for this category. The finding here is medium: the guard saw a sign, not a proof.
The instructions or scripts send data out: environment variables, keys, file contents, chat history. You may never notice, because the agent performs the upload as "part of the task".
If the upload is not needed for the task, remove it: catalogs flag such skills and delist them. If it is needed, name the destination explicitly, say what leaves the machine, and give the user a switch.
How to improve
- Say in the description WHEN to use the skill ("use when…", example requests): that is the agent's main cue.
- Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
- A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.
Guard findings · 10
✓ No critical or high findings
Medium and low: 10
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medium Exfiltration
exfil-secret-in-urlSKILL.md:233Credential passed in a URL query string (normal for some APIs — verify the host is the intended service) (quoted — discussed, not commanded)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=1&get_received_offers=1&active_only=1&get_descriptions=1&language=…" \
quoted -
medium Exfiltration
net-credential-useSKILL.md:233Credential used in a network call (verify the destination is the intended service)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=1&get_received_offers=1&active_only=1&get_descriptions=1&language=…" \
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medium Exfiltration
exfil-secret-in-urlSKILL.md:239Credential passed in a URL query string (normal for some APIs — verify the host is the intended service) (quoted — discussed, not commanded)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=0&get_received_offers=1&active_only=1&get_descriptions=1&language=…" \
quoted -
medium Exfiltration
net-credential-useSKILL.md:239Credential used in a network call (verify the destination is the intended service)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=0&get_received_offers=1&active_only=1&get_descriptions=1&language=…" \
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medium Exfiltration
exfil-secret-in-urlSKILL.md:245Credential passed in a URL query string (normal for some APIs — verify the host is the intended service) (quoted — discussed, not commanded)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=1&get_received_offers=0&active_only=1&get_descriptions=1&language=…" \
quoted -
medium Exfiltration
net-credential-useSKILL.md:245Credential used in a network call (verify the destination is the intended service)curl -s "https://api.steampowered.com/IEconService/GetTradeOffers/v1/?key=…&get_sent_offers=1&get_received_offers=0&active_only=1&get_descriptions=1&language=…" \
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medium Exfiltration
exfil-secret-in-urlSKILL.md:252Credential passed in a URL query string (normal for some APIs — verify the host is the intended service) (quoted — discussed, not commanded)curl -s "https://api.steampowered.com/IEconService/GetTradeOffer/v1/?key=…&tradeofferid=…&language=…&get_descriptions=1" \
quoted -
medium Exfiltration
net-credential-useSKILL.md:252Credential used in a network call (verify the destination is the intended service)curl -s "https://api.steampowered.com/IEconService/GetTradeOffer/v1/?key=…&tradeofferid=…&language=…&get_descriptions=1" \
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medium Exfiltration
net-credential-useSKILL.md:259Credential used in a network call (verify the destination is the intended service)curl -s "https://api.steampowered.com/IEconService/GetTradeOffersSummary/v1/?key=…&time_last_visit=0" \
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low Exfiltration
exfil-secret-in-urlSKILL.md:169Credential passed in a URL query string (normal for some APIs — verify the host is the intended service) (placeholder value)-H "Referer: https://steamcommunity.com/tradeoffer/new/?partner=…&token=…" \
placeholder
Files scanned: 2. Evidence is masked. Grey chips explain why severity was lowered.
Against the Agent Skills spec
- warning
description-no-whendescription does not say WHEN to use the skill (no "use when") - note
frontmatter-keyunknown frontmatter key "homepage"
Process rating: all ten parameters 55/100
- 0Inputs and preconditions. Does not say what the process needs to start
- 20When it triggers. No condition that starts the skill
- 30Running it twice. 11 mutating operations with no state check
- 40Consistency. Frontmatter name (steam-community-inventory) differs from the folder (steamcommunity)
- 60Tools and files. Uses tools (web) that frontmatter does not declare
- 60Result and completion. Output format stated, no completion criterion
- 60Failures and branches. 2 branches
- 100Steps. 26 steps
- 100Execution cost. Instruction body is 3090 tokens
- 100Progress reporting. Reports progress
Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.
Quality signals
- +5Description has no quoted example phrases that should trigger the skill
- +4Description does not say when NOT to use the skill (false activations)
- +3Description length 77: 120–800 characters recommended
- +1No license
- +2Single-language instructions
- +4Structure: 24 headings
- +3Step-by-step instructions: 26 items
- +3Output format is stated explicitly
- +4Has examples (19 code blocks)
Quality base 70; lint remarks subtract, signals add up to 100. Result: 71.