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    Repair Cookie Scope Leakage

    1

    Repair cookie scope leaks caused by incorrect Domain, Path, Secure, SameSite, host-only, public-suffix, port, or redirect handling.

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    Repair Cookie Scope Leakage

    Repair Cookie Scope Leakage

    Example session with this skill installed

    Our Python SDK cookie jar treats host-only cookies as Domain cookies and matches Path with startswith, so /app cookies leak to /application and sibling subdomains. Repair with local fake requests. Preserve expiry, SameSite, Secure, redirect, and session behavior; never log cookie values.

    • Read your context and instructions
    • Compiled the repair cookie scope

    Cookie authority defect found. Storage loses the host-only flag and request matching uses raw string prefixes, widening both domain and path scope. The repair preserves canonical scope metadata, applies directory-boundary path matching, keeps Secure/SameSite/expiry/session policy intact, and validates sibling domains, exact paths, deletion, redirects, and redacted telemetry without exposing cookie values.

    Connects securely to your tools. The creator never sees your data.

    About this skill

    The problem

    Cookie storage and matching logic in custom SDKs or proxies often grant broader authority than the Set-Cookie contract allows. This leads to security leaks where host-only cookies are sent to subdomains or secure cookies leak over unencrypted channels.

    What it does

    • Identifies failures in host-only, Domain, and Path matching logic within the repository.
    • Patches Set-Cookie parsing to enforce canonical storage identity and public-suffix boundaries.
    • Fixes deletion logic where different scopes prevent session cleanup.
    • Corrects request attachment paths to prevent cookies from leaking to sibling tenants or parent domains.
    • Implements redacted observability and deterministic local fixtures for regression testing.

    Why this beats prompting it yourself

    Manual prompts often overlook the nuance between host-only and Domain-level cookies, leading to incomplete fixes that break session persistence. This skill enforces a strict canonical contract for normalization and validation, ensuring repairs align with browser-compatible security standards without leaking secrets in logs.

    Use cases

    • Preventing session cookies from leaking to sibling subdomains in multi-tenant apps.
    • Fixing broken cookie deletion logic caused by scope mismatches.
    • Enforcing Secure and SameSite attributes in custom proxy or client implementations.
    • Standardizing Path matching to prevent string prefix overlaps from leaking data.

    Known limitations

    Does not contact production services or read live secrets. Repository-level IDNA and public-suffix support depend on existing local libraries.

    Find more skills like this on the Claude Skills Marketplace, the Codex Skills Marketplace and the Gemini Skills Marketplace, or browse Claude Skills for Agents & Orchestration.

    Cannot choose or change browser-compatible security, session semantics, expiry, SameSite, partitioning, redirect policy, and public errors; cannot verify production infrastructure or prove every runtime, proxy, network, or scheduler ordering.

    How to use

    1. 1

      Connect your agent to the Agensi MCP

      Copy the prompt and paste it into Claude, ChatGPT, Cursor or any agent that supports MCP. It sets up the connection for you. Manual setup

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    3. 3

      Ask for what you need

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    Recently published to Agensi

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    Trust & safety

    Security scan

    Security scan passed 2 months ago

    Permissions

    Terminal / Shell
    Read Files
    Write Files

    Run on a clean branch with repository files and disposable local fixtures. Review every patch and validation result before merge. Keep production services, real credentials, customer payloads, and deployment out of scope.

    Listed2 months ago
    Updated9 days ago

    What's inside

    Frequently Asked Questions

    This skill specifically targets and repairs logic errors in custom SDKs or proxies where cookies are inadvertently shared across subdomains or sent over unencrypted channels due to improper scope matching.

    The skill is designed to work with most leading AI coding assistants and agents; it requires repository access to analyze your cookie handling logic and Set-Cookie parsing code.

    No, this skill operates exclusively at the repository level to fix code logic and creates deterministic local fixtures for testing; it never accesses production environments or live session data.

    You receive the specialized agent logic for identifying and patching scope vulnerabilities, a suite of regression test templates, and documentation for enforcing browser-compatible security standards.

    It automatically detects if your environment has necessary Public Suffix List or IDNA libraries and will configure its patches to leverage your existing dependencies for domain validation.

    New in Agents & Orchestration