mirrord-propagation-discovery

1# mirrord Propagation Discovery Skill
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3> mirrord routes a request to a developer's local process when the request matches an HTTP filter. On a shared cluster that filter has to pick out **one developer's requests at every service the request passes through**, so the value it matches on must already travel with the request across all hops. This skill finds that value in a live environment instead of assuming one: it dumps the traffic arriving at each service with `mirrord dump`, checks which identifiers survive from the edge to the last hop, and turns the best one into a `mirrord.json` filter. The sister skill `mirrord-header-propagation` changes code to make `baggage` propagate; this one changes nothing and tells you what already works.
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5## Security Boundaries
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7> **IMPORTANT:** Follow these rules for all operations in this skill.
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9- **Mirror only, never steal, during discovery.** `mirrord dump` copies traffic; the target keeps answering every request. Don't run a `steal` session or an unfiltered session against a shared target while scanning. The only cluster-side effect is the short-lived mirrord agent pod (or ephemeral container) each dump creates.
10- **Staging and development clusters only.** Dumps print real request content. Don't point them at production.
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