Module: RailsAiContext::JsonBudget

Defined in:
lib/rails_ai_context/json_budget.rb

Overview

Fits a data structure into a character budget and serializes it as JSON that always parses.

A tool response is markdown and can be cut anywhere, so BaseTool#text_response slices the string. Resource payloads are served under an application/json mime type, so the same trick ends the body mid-object and JSON.parse raises. The budget is applied to the DATA instead: whole elements are dropped until what remains fits, and what went missing is reported under a reserved "_truncated" key. Values are otherwise served exact, except an over-long string, which is cut at a marker and counted in the report.

Defined Under Namespace

Classes: Taken

Constant Summary collapse

TRUNCATION_KEY =

Reserved key carrying the reduction report on an oversized payload, and the marker left inside a string value that had to be cut.

"_truncated"
TRUNCATION_REASON = 
"response_size_cap"
STRING_CLIP_MARKER = 
"... (truncated)"
TRUNCATION_HINT = 
"Whole elements were dropped and an over-long string value may be cut at a " \
"\"#{STRING_CLIP_MARKER}\" marker; nothing else was altered. " \
"Use the rails_get_* tools to page through what is missing."
MAX_REDUCE_DEPTH =

How deep the reducer descends before it empties a container instead of recursing. Introspection payloads bottom out far above this; the cap is here so a pathological structure cannot drive unbounded recursion.

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NOTE_RESERVE =

Chars held back from the data budget for the report, how many clipped paths it names, and how many refits are allowed when a report outgrows the reserve. The reserve is capped at a quarter of the budget so a small budget still leaves room for data.

2_048
MAX_CLIP_RECORDS = 
12
MAX_FIT_ATTEMPTS = 
3
NOTE_ATTACH_OVERHEAD =

Chars it costs to attach the report to a fitted payload, whichever shape with_note ends up using. Slack, not a tight bound.

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MINIMUM_TRUNCATION_JSON =

Smallest valid JSON that still says the payload was cut. Emitted only when the budget is below the size of a usable report.

%({"#{TRUNCATION_KEY}":true})

Class Method Summary collapse

Class Method Details

.for_resource(data) ⇒ Object

Resource payloads ride a single JSON-RPC frame with no transport-level size guard, so they get the same char cap tool responses do: a huge schema or routing table must not produce an unbounded payload.



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# File 'lib/rails_ai_context/json_budget.rb', line 56

def for_resource(data)
  generate(data, RailsAiContext.configuration.max_tool_response_chars)
end

.generate(data, max) ⇒ Object

Pretty JSON when the payload fits, a reduced compact document when it does not. Never returns a string that fails to parse.



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# File 'lib/rails_ai_context/json_budget.rb', line 62

def generate(data, max)
  content = JSON.pretty_generate(data)
  return content unless max && content.length > max

  # Indentation alone can be the whole overage. Dropping it loses no
  # data, so try that before reducing: the reducer works against a
  # budget held back for its report and would otherwise clip a payload
  # that fits, and report a loss that did not happen.
  compact = JSON.generate(data)
  return compact if compact.length <= max

  reduce_to_budget(data, content.length, max)
end