Infer the type and effect row of the expression at a source location (1-based line and character column) in a .hird file. Use it for 'what is the type here', including local bindings, sub-expressions, and names inside use lists; for a named top-level definition prefer lookup_definition, and for a function's effects with explanations prefer explain_effect_row. Returns token (the source token found at the location), type (the normalized type as Hirð prints it), and effect_row (the row of a function-typed expression, {} otherwise). A location outside the file is invalid_params; one with no typed expression is not_found. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Look up a top-level definition by name: defining file and line, kind, type, and doc comment. Use it first to locate or identify a symbol; use get_context_for_symbol when you also want effects, callers, and callees, explain_effect_row to interpret a function's effects, and render_ir_fragment for its body. Returns kind (function, type, constructor, effect, tool, tool_function, actor, message_type, message_constructor, supervisor, or extern), line, and nullable type and doc; file is the sibling module when the name is imported. An unknown name is not_found, with every name in the file's scope in error.data.available. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Explain a function's effect row: the canonical row plus a one-sentence explanation of each effect. Use it for 'what may this function do' or to interpret an unfamiliar effect. It covers one named function; use infer_type for an arbitrary expression's row and emit_actor_effect_graph for what an actor transitively does. Returns type, effect_row, open (the row ends in a row variable, so it may carry more effects than listed), pure (closed and empty), and effects, each with effect and explanation. A name of non-function type is not_a_function; an unknown name is not_found with the available names in error.data.available. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Render the typed intermediate representation (IR) of one top-level definition as JSON. Use it when the exact lowered structure matters: desugared bodies, the resolved type on every node, a tool's generated function. The IR is verbose and follows the compiler's declaration serialization, so for a human-oriented view prefer get_context_for_symbol or lookup_definition. Returns module, name, and ir (the serialized declaration). An unknown name is not_found with the available names in error.data.available. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Describe one actor's protocol: its message type and constructors, state type, init parameters and effects, per-handler effect rows, and the declared effect summary. Use it to learn how to talk to an actor or what each handler may do; use emit_actor_effect_graph for the actors, supervisors, and tools it reaches transitively, and lookup_definition if you only need its location. Returns actor with name, line, state, message (name, constructors), init (params, effects), handlers (message, effects), and effects; types and rows carry a display string. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Emit the actor/effect graph rooted at one actor: every actor reachable through Send, Await, Spawn, and Schedule effects (matched by message type), every supervisor of an included actor together with its whole child set, and every tool an included actor's effect summary names. Use it for 'what does this actor transitively do or depend on'; effect rows are per-process, so no single signature shows this. Use explain_actor_protocol for one actor's own interface and get_context_budget to gauge the size before requesting it. Returns schema_version (1), module, root, and the included actors, supervisors, and tools, whose nodes share the shape of hird emit-effect-graph --json; declarations the root does not reach are omitted. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Summarize one symbol for an LLM prompt within an approximate token budget: signature, effect row, doc comment, callers, and callees, added in that order while they fit. Use it as the default way to bring a symbol into context; use lookup_definition for just the location, explain_effect_row for effect explanations, and render_ir_fragment for the full body. Returns kind, the budget applied, summary (prompt-ready text), approx_tokens (its estimated cost at ~4 characters per token), and omitted (the sections that did not fit). The signature is always present, truncated when the budget is smaller than it. An unknown name is not_found with the available names in error.data.available. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.

Estimate the token cost of loading a file's declarations into an LLM context window, per category: types, effects, actors, supervisors, tools, and function signatures. Use it before pulling a module in wholesale, to choose between get_context_for_symbol calls and a full read, or to pick a budget; it names no individual symbols. Returns approx_tokens with types, effects, actors, supervisors, tools, functions, and total, estimated at ~4 characters per token from one-line signatures, and a note restating that. Fails only when the file is unreadable or has parse or type errors. Read-only: compiles the file's directory in memory (cached until a sibling changes) and writes or executes nothing. Failures are isError results with a stable error.code: file_not_found, read_error, invalid_params, parse_error, or check_error, the last two carrying coded diagnostics in error.data.diagnostics.