01 · Surface
What can the peer expose?
List resources, tools, prompts, skills, endpoints, modalities, and extension points. Do not summarize a broad mission as if it were an invocable capability.
Foundation 03 · Discovery and negotiation
Inspect the interface
before you delegate.
Capability discovery is a precondition for a legible handoff. Read what a peer declares, compare it with the request, identify unsupported operations and modalities, and keep authentication and authorization questions visible.
Learning boundary. Capability metadata describes an interface at a point in time. It does not prove that the capability works, that a peer is trustworthy, that a user has authorized the action, or that a declared skill produces a correct result.
Learning objective
Turn a capability card into a preflight decision.
By the end of this lesson, you should be able to compare required inputs and outputs with declared capabilities, modalities, extensions, authentication requirements, and unsupported operations before a workflow hands over context or authority.
02 · Fit
Does the task match?
Compare required inputs, output types, latency, state, and failure handling with the declared interface. Record mismatches as a hold or escalation.
03 · Access
Who may use it?
Separate discovery from authentication and authorization. A visible endpoint or Agent Card does not grant permission to send data or request an effect.
04 · Change
What if the surface moves?
Record the version, extension, source, freshness, and recheck trigger. A capability declaration can become stale without the route disappearing.
Practice lab
Choose a peer without over-reading its card.
Two remote agents advertise “research assistance.” One accepts text and files with asynchronous tasks; the other accepts text only and lists a custom extension. Neither public description states whether external actions are permitted.
- Write the minimum capability set needed for the requested workflow.
- List what each declaration supports and what it leaves unknown.
- Define the authorization and data-sharing checks required before sending context.
- Specify the hold condition if the task needs a modality or effect that is not declared.
Source shelf
Study discovery models and application consent.
- Model Context Protocol specificationStudy capability negotiation and the server/client features for resources, prompts, tools, sampling, roots, and elicitation, alongside the specification’s application-level consent principles.
- Agent2Agent Protocol specificationRead the Agent Card, capabilities, skills, modalities, authentication requirements, extensions, and capability-validation patterns before designing a remote-agent handoff.
Continue the pathway