Flight Deck reduces guesswork before an MCP call without turning planning into execution. Discovery, descriptor inspection, static validation, effect preview, and invocation planning stay read-only; the real capability still runs only under its own authority and must be followed by authoritative postcondition evidence.
Discover the caller-effective capability first
GDP does not require clients to hard-code one permanent tool count or assume every runtime exposes the same surface. inspect_server describes the current effective catalog and policy identity, while search_tools searches only that caller-effective descriptor set.
After discovery, inspect_tool returns the exact descriptor, input schema, annotations, execution policy, and authority summary for one capability. inspect_authority separates runtime visibility, policy knowledge, target readiness, and still-unproven consent or downstream availability; inspect_limits exposes non-secret server and schema bounds without reserving capacity.
Use exact names returned by current discovery instead of guessing a historical tool name.
Treat catalog identity as a precondition when a later validation or plan depends on the same surface.
A visible tool describes a requestable capability; it does not prove permission to execute it.
Caller profile, enabled capabilities, host loading behavior, and runtime version can narrow the effective catalog.
Validate, preview, and plan without executing
validate_tool_call checks one proposed JSON argument object against the effective descriptor, catalog precondition, bounded schema, static execution policy, and exact repository target when the tool is repository-scoped. It does not invoke or queue the target capability.
preview_tool_call builds on that static validation to describe bounded predicted effects such as caller-only output, a local journal record, or a queue item. compile_invocation_plan then preserves caller order for up to a bounded set of explicit calls and records per-step blockers, effect classes, replay classes, target identity, and stop conditions.
A valid call shape means static preconditions passed; it does not prove future workspace state.
A preview describes what the call is expected to affect; it is not an effect receipt.
A compiled plan records execution_authorized=false and execution_started=false because planning grants no authority.
If the catalog changes, the target disappears, argument validation changes, required approval is missing, or an authoritative postcondition is not observed, stop and refresh rather than continuing from the stale plan.
Keep static admissibility separate from consent and outcome
Flight Deck diagnostics intentionally report user consent, downstream availability, and future execution outcome as unproven unless another authoritative layer establishes them. A false proof boolean in these diagnostics means not proven by that read-only check, not automatically denied.
Only an explicit static blocker or an execution-time authority error is denial evidence. Conversely, static_request_blocked=false only means the request is admissible at the checked static layer; it still does not guarantee that a local policy, user decision, external service, or later repository state will permit successful execution.
Use Flight Deck to remove preventable ambiguity before execution, not to manufacture approval that belongs to another authority layer.
Execute the exact capability, then read postconditions
Refresh the effective catalog or exact target when either could have changed since preflight.
Invoke the intended capability under its own execution policy and local authority boundary.
For queueing tools, distinguish the intake receipt from any later local apply or run.
Read the applicable GDP operation, repository, check-run, or proof evidence for the material outcome.
Continue only from the first step whose authoritative postcondition remains unproven.
Flight Deck is strongest when paired with Proof: preflight answers whether a proposed call is structurally ready; fresh GDP evidence answers what the real call actually accomplished.
