BC snaprender
Give your agent eyes on the web — screenshot any URL as an image file. Supports device emulation (iPhone, iPad, Pixel, MacBook), dark mode, full-page scroll, ad blocking. Uses exec tool with curl (NEVER the browser tool). $SNAPRENDER_API_KEY is pre-set. See instructions below.
As a process C 57/100 · Has gaps — weak spots: result and completion, inputs and preconditions
How to improve
- Say in the description WHEN to use the skill ("use when…", example requests): that is the agent's main cue.
For the model run — optional
- 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 · 2
✓ No critical or high findings
Medium and low: 2
-
low Exfiltration
net-credential-useSKILL.md:3Credential used in a network call (verify the destination is the intended service) (detector / deny-list definition)description: "Give your agent eyes on the web — screenshot any URL as an image file. Supports device emulation (iPhone, iPad, Pixel, MacBook), dark mode, full-page scroll, ad blocking. Uses exec tool
detector -
low Exfiltration
net-credential-useSKILL.md:130Credential used in a network call (verify the destination is the intended service) (detector / deny-list definition; the skill's own vendor host)jq -n --arg url 'https://stripe.com' '{url: $url, response_type: "json", format: "jpeg", quality: 60, block_ads: true, block_cookie_banners: true}' | curl -s -X POST "https://app.snap-render.com/v1/scdetectorvendor-host
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")
Process rating: all ten parameters 57/100
- 0Result and completion. Does not say what the result is
- 0Inputs and preconditions. Does not say what the process needs to start
- 50When it triggers. No condition that starts the skill
- 50Failures and branches. 0 branches, has a failure section
- 60Tools and files. Uses tools (bash, web) that frontmatter does not declare
- 100Steps. 13 steps
- 100Consistency. Name and required fields are in place
- 100Execution cost. Instruction body is 1618 tokens
- 100Running it twice. No mutating operations
- 100Progress reporting. Reports progress
- medium Safety rules and hard prohibitions inside a skill: they belong in the system prompt, here they protect nothing
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)
- +3Output format is not stated: the model decides each time
- +1No license
- +2Single-language instructions
- +3Description length 277: enough signal without eating the budget
- +4Structure: 10 headings
- +3Step-by-step instructions: 13 items
- +4Has examples (6 code blocks)
Quality base 70; lint remarks subtract, signals add up to 100. Result: 72.
External checks
ClawHub: clean
SnapRender is a coherent screenshot-rendering skill, but users should remember that URLs, HTML, Markdown, and signed screenshot links are sent to an external service.
LLM: benign (medium) · VirusTotal: benign · 28 May 2026