Agent Skill
Mirrord Propagation Discovery skill
mirrord-propagation-discoverymetalbear-co/mirrordmirrord/mcp/corpus/skills/mirrord-propagation-discovery/SKILL.md
Scans a live Kubernetes environment with `mirrord dump` to find an identifier mirrord can filter traffic on: a header, a `baggage` or `tracestate` member, a tenant or user id, a trace id (W3C, B3, X-Ray, Google, Jaeger), a JWT claim, a cookie, a path segment, or a JSON body field that is present on every hop of a request chain, unique to one developer's traffic, and settable by that developer. Runs mirror-only dumps on each service, sends a tagged probe request at the edge or observes real traffic, scores the candidates, and produces the matching `http_filter` (regex, jq on headers, path, method, body, or combinations) plus a per-hop report of where each identifier is dropped. Installs the mirrord CLI through a package manager when it is missing. Use when the user asks what to filter on, whether the cluster already propagates a request id or trace context, how to isolate their own requests on a shared staging cluster, how to filter on a JWT or cookie with mirrord, or wants to inspect live traffic with mirrord dump. Changes no application code: propagation gaps go to the mirrord-header-propagation skill.
always on
273 tokname + description
once used
4,050 tokSKILL.md body
bundled files
651 KB
repo stars
5.4kGitHub
Install the Mirrord Propagation Discovery skill
Skills CLI (Claude Code, Codex, Cursor and others)
npx skills add https://github.com/metalbear-co/mirrord --skill mirrord-propagation-discovery
Claude Code, by hand (all projects)
git clone --depth 1 https://github.com/metalbear-co/mirrord.git /tmp/mirrord mkdir -p ~/.claude/skills cp -R /tmp/mirrord/mirrord/mcp/corpus/skills/mirrord-propagation-discovery ~/.claude/skills/mirrord-propagation-discovery
For one project only, copy the folder into .claude/skills/ in that project instead. The agent picks it up when a task matches its description.
What it costs your context
Agent Skills load in three steps. Tokens counted with the o200k tokenizer; your model's count will differ a little.
| When | What loads | Cost |
|---|---|---|
| Every session | Name and description | 273 tok |
| When the agent uses it | The SKILL.md instructions | 4,050 tok |
| Only if opened | 6 bundled files (51 KB) | varies |
Until it is used, mirrord-propagation-discovery costs about 5.0× less than the median MCP server we measured (1,362 tokens on every turn). Installing all 12 skills from metalbear-co/mirrord would load 1,593 tokens of descriptions. Skills vs MCP study
Checks
- The description is longer than the specification's 1,024-character limit, so some agents may cut or reject it.
Checked 2026-10-22 · method
What's inside
The headings of its SKILL.md. Read the full file on GitHub.
- mirrord Propagation Discovery Skill
- Security Boundaries
- What "usable" means
- Workflow
- Step 1: Prerequisites and install
- Step 2: Map the hops
- Step 3: Dump the hops
- Step 4: Score the candidates
- Step 5: Build the filter
- Step 6: Verify with a live session
- Step 7: Hand off the gaps
- Final report
- What NOT to Do
More skills from metalbear-co/mirrord
- mirrord-chaosmetalbear-co/mirrord
Help users chaos test their app with mirrord: inject artificial latency or connection errors into a mirrord session's outgoing traffic via per-session chaos rules managed with the `mirrord chaos` CLI. Use when a user wants to add latency or delay to outgoing connections or a dependency (e.g. a slow database), simulate connection failures (reset, timed out, refused), test app behavior under degraded network conditions, or wire chaos rules into CI test runs. Always use this skill instead of the deprecated _experimental_.latency mirrord config option.
5.4k119 tok idle · 3,421 in use - mirrord-cimetalbear-co/mirrord
Help users set up mirrord in CI pipelines for testing against real Kubernetes environments. Use when users want to run end-to-end tests, integration tests, or automated tests in CI using mirrord to connect to staging/shared clusters.
5.4k52 tok idle · 3,331 in use - mirrord-configmetalbear-co/mirrord
Helps users generate, edit, and validate mirrord.json configuration files for mirrord (MetalBear). Use when the user wants to connect their local process to a Kubernetes environment, configure features (env/fs/network), or needs feedback on an existing mirrord.json. Always ensures output JSON is valid and schema-conformant.
5.4k72 tok idle · 2,643 in use - mirrord-db-branchingmetalbear-co/mirrord
Helps users configure mirrord.json for database branching, enabling isolated database copies for safe development and testing. Use when the user wants to set up MySQL, MariaDB, PostgreSQL, MSSQL, MongoDB, Redis, DynamoDB, ClickHouse, Google Spanner, Amazon S3, turbopuffer, or generic branches, configure copy modes, connection sources, schema migrations, IAM authentication, or manage database branches.
5.4k94 tok idle · 17,404 in use - mirrord-header-propagationmetalbear-co/mirrord
Makes a codebase propagate W3C baggage (the `baggage` header carrying `mirrord-session=<key>`) end to end, so mirrord HTTP filters, preview environments, and queue splitting can route a whole request chain to one developer's session. Detects existing OpenTelemetry, Datadog, or other tracing that can already propagate baggage and enables it; otherwise adds a small propagation layer. Covers inbound/outbound HTTP and gRPC, publishing to and consuming from Kafka, RabbitMQ, SQS/SNS, GCP Pub/Sub, Azure Service Bus, NATS, Redis Pub/Sub, BullMQ and Temporal, per-message context restore in consumers, and storage hand-offs such as a GCS signed URL upload that triggers Pub/Sub or an S3 presigned upload that triggers SQS. Ends with a report of every flow found and which ones still drop the header. Use when the user asks to propagate headers, baggage, tracestate, the mirrord session key, or trace context across services or queues, or when a mirrord filter matches the first service but not downstream services or queue consumers.
5.4k237 tok idle · 4,164 in use - mirrord-kafkametalbear-co/mirrord
Helps DevOps engineers configure mirrord Operator's Kafka queue splitting feature end-to-end. Generates the MirrordSplitConfig and MirrordPropertyList Kubernetes CRD YAMLs (the current resources; MirrordKafkaTopicsConsumer + MirrordKafkaClientConfig are deprecated but still supported), the matching mirrord.json split_queues section with message_filter and jq_filter, and Helm value guidance. Use this skill whenever the user mentions Kafka splitting with mirrord, MirrordSplitConfig, MirrordPropertyList, MirrordKafkaClientConfig, MirrordKafkaTopicsConsumer, Kafka queue/topic splitting, configuring mirrord with Kafka, Kafka Streams splitting, MSK IAM auth, or troubleshooting Kafka splitting sessions. Also trigger on split_queues with queue_type Kafka, or connecting mirrord to a Kafka cluster. This is a Team/Enterprise feature of mirrord.
5.4k188 tok idle · 6,045 in use - mirrord-operatormetalbear-co/mirrord
Help users install and configure the mirrord Operator for team/enterprise environments. Use when users ask about operator setup, Helm installation, cloud API key or license configuration, air-gapped/offline licensing, enabling features (queue splitting, DB branching, preview environments, multi-cluster), internal registries, OpenShift/GKE Autopilot, RBAC, or multi-user mirrord deployments. Also use when an AI agent hits a Team or Enterprise feature on a cluster with no license and needs to offer the user a trial (agent-started trial; the trial is Enterprise tier).
5.4k124 tok idle · 6,107 in use - mirrord-prev-envmetalbear-co/mirrord
Help users create and manage mirrord preview environments — running a modified service as an isolated pod in a shared Kubernetes cluster, scoped by an environment key and HTTP/queue traffic filtering, so teams can validate and review changes against real traffic without affecting live services. Use when a developer wants to run "mirrord preview" ad hoc, share a preview via a link (mirrord-share-ingress), or wire preview environments into CI with the metalbear-co/mirrord-preview GitHub Action (e.g. per-PR previews, least-privilege cluster access).
5.4k122 tok idle · 9,633 in use