Gear Message Execution

Goal

Provide a focused local path for reasoning about message flow and execution behavior in standard Gear/Vara Sails work.

Inputs

• ../../references/gear-execution-model.md
• ../../references/gear-sails-production-patterns.md
• ../../references/gear-messaging-and-replies.md
• ../../references/gear-gas-reservations-and-waitlist.md
• ../../references/scale-binary-decoding-guide.md
• ../../references/sails-syscall-mapping.md

Route Here When

• replies, timeouts, or error replies are surprising
• delayed work spans future blocks
• reservations or waitlist behavior affect the design
• a builder is mixing raw payload handling into an otherwise standard Sails flow
• raw hex, reply bytes, event bytes, or metadata-vs-IDL decoding path is unclear
• a reply from a hardcoded non-program ActorId does not decode as a Sails route; route to gear-builtin-actors for the matching gbuiltin_*::Response type

Working Model

1. Confirm what executes now versus after the next block.
2. If raw bytes are involved, classify the source first: constructor, service payload, reply, event, full state, or state-function output.
3. Determine whether the bytes are Sails-routed, plain SCALE, or metadata-driven state output.
4. Match the decoder artifact to the source: generated client or .idl, ProgramMetadata, or state.meta.wasm.
5. Identify whether the path is fire-and-forget, reply-driven, delayed, or reservation-backed.
6. Separate transport failure, timeout, and error reply.
7. Check whether rollback should revert local state if a send or reply path fails.
8. If the path is in tests, confirm the block-advance pattern and expected reply timing.

Guardrails

• Treat reply, timeout, and late hook execution as distinct states.
• Keep staged payload flows paired with their commit step.
• Treat reservation duration and waitlist expiry as architecture constraints.
• Use exec::gas_available() (or Syscall::gas_available() if using Sails) when checking available gas during the current execution.
• Prefer generated Sails clients unless debugging the route or codec layer.
• If a Sails route is involved, expect Sails Header-aware encoding rather than a raw struct payload.
• Keep the guidance on the standard Gear/Vara Sails path.
• Prefer local repo references over external skill dependencies.
• Do not start with plain Decode::<T> on arbitrary bytes when a Sails route may be involved.
• Match decode artifact to source: generated client or .idl for standard Sails interface paths, ProgramMetadata for full state, and state.meta.wasm for state-function output.
• Treat gear-meta as a debugging fallback, not the first-choice default path.