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tessl-academy/tessl-change-review-walkthrough

Guided walkthrough for the Reviewing your changes with tessl change review lesson: run a change review over a real diff with a code-review skill, read the summary, inline hunk comments, and unplaced findings, and see how the structured output feeds a GitHub review.

75

Quality

94%

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SecuritybySnyk

Low

Low-risk findings worth noting

Overview
Quality
Evals
Security
Files

Low

Low-risk findings.

2 low severity findings. Worth noting, but not necessarily harmful.

Low

W011: Third-party content exposure detected (indirect prompt injection risk).

What this means

The skill exposes the agent to untrusted, user-generated content from public third-party sources, creating a risk of indirect prompt injection. This includes browsing arbitrary URLs, reading social media posts or forum comments, and analyzing content from unknown websites.

Why it was flagged

The required runtime workflow invokes `tessl change review`, which “pulls one from the registry” and then runs a model to generate review text; this implies the agent/CLI will ingest outsider-authored content (the selected reviewer skill from a public registry and/or the diff content from the learner’s repo) into the LLM context, creating an indirect prompt-injection surface.

Where we found it

learner's git diff content

content-type · 4 sites

The tessl change review command ingests the learner's git diff into an LLM for review, which is outsider-authored content relative to the plugin.

SKILL.md

40

tessl change review --skill tessl/code-review#review-code-legibility --base origin/main

SKILL.md

62

tessl change review --skill tessl/code-review#review-code-legibility --json

SKILL.md

63

tessl change review --skill tessl/code-review#review-code-legibility --output review.json

SKILL.md

74

tessl change review --skill tessl/code-review#review-code-legibility

registry-hosted reviewer skill content

content-type · 5 sites

The tessl CLI fetches a reviewer skill from a public registry at runtime, and its content (prompts/instructions) is ingested into the LLM context, creating an indirect prompt-injection surface via the registry-hosted skill.

SKILL.md

31

the command pulls one from the registry

SKILL.md

40

tessl change review --skill tessl/code-review#review-code-legibility --base origin/main

SKILL.md

62

tessl change review --skill tessl/code-review#review-code-legibility --json

SKILL.md

63

tessl change review --skill tessl/code-review#review-code-legibility --output review.json

SKILL.md

74

tessl change review --skill tessl/code-review#review-code-legibility

Report incorrect finding
Low

W012: Unverifiable external dependency detected (runtime URL that controls agent).

What this means

The skill fetches instructions or code from an external URL at runtime, and the fetched content directly controls the agent’s prompts or executes code. This dynamic dependency allows the external source to modify the agent’s behavior without any changes to the skill itself.

Why it was flagged

The tessl CLI explicitly "pulls one from the registry" and the lesson runs `tessl change review --skill tessl/code-review#review-code-legibility`, so the reviewer skill (tessl/code-review#review-code-legibility) is fetched at runtime and can provide external prompts/instructions that control the review execution.

Where we found it

tessl/code-review#review-code-legibility

dependency · 4 sites

The reviewer skill tessl/code-review#review-code-legibility is fetched at runtime from a public registry by the tessl CLI and provides external prompts/instructions that control the review execution.

SKILL.md

40

tessl change review --skill tessl/code-review#review-code-legibility --base origin/main

SKILL.md

62

tessl change review --skill tessl/code-review#review-code-legibility --json

SKILL.md

63

tessl change review --skill tessl/code-review#review-code-legibility --output review.json

SKILL.md

74

tessl change review --skill tessl/code-review#review-code-legibility

Audited
Security analysis
Snyk