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-# Observations
-
-Running notes on design decisions, experiments, and lessons learned during
-development. Entries are roughly chronological.
-
----
-
-## Tool Schema Complexity and Model Capability
-
-**Context.** The execute package originally exposed a single `execute_code`
-tool with a flexible schema: callers could pass inline `steps`, a `pipe` array
-for sequential stdin-chained execution, tool-name references, parallel fan-out
-groups, elevated steps, and a sandbox selector — all through one JSON object.
-
-**Observation.** Larger models with strong reasoning ability (e.g. frontier
-chat models and extended-thinking variants) handled the unified schema well.
-They correctly discriminated between the `steps` and `pipe` fields, chose
-appropriate execution modes, and composed pipelines without confusion.
-
-Smaller models struggled. Common failure modes:
-
-- Emitting both `steps` and `pipe` in the same call, producing ambiguous or
-  undefined behaviour.
-- Using `pipe` where `steps` was correct (or vice versa), because the
-  distinction between "parallel batch" and "stdin pipeline" was not obvious
-  from a single tool description.
-- Ignoring the `tool` field inside a step and writing inline shell code that
-  reimplemented an existing named tool.
-
-**Decision.** Split `execute_code` into three purpose-specific tools:
-
-| Tool | Input key | Purpose |
-|------|-----------|---------------------------|
-| `execute_code` | `steps` | Arbitrary inline code. Each step is independent; read-safe steps may run in parallel automatically. |
-| `call_tool` | `calls` | Named scripts from the tools directory. Inline `code` fields are rejected at dispatch. |
-| `pipe` | `stages` | Sequential pipeline. stdout of each stage feeds stdin of the next. Stages may be inline code or named tools. |
-
-The `parallel` option (a `parallel` array inside a step) is retained in
-`execute_code` and `pipe` for fan-out within a stage. This gives smaller
-models a clear, narrow contract per tool without removing any capability.
-
-**Trade-off.** Sophisticated models now make three tool choices where they
-previously made one. For those models this is a minor regression in ergonomics.
-The bet is that the schema clarity gained at the smaller-model end outweighs
-the slight overhead at the larger-model end, and that a well-prompted larger
-model will use the right tool consistently regardless.