# Investigation context v5

Historical v5 format; the current measurement CLI defaults to v7. Use
`--target-version investigation_project_v5` to reproduce this version.

New project-backed investigation contexts use `investigation_project_v5`.
Existing frozen contexts keep their version and exact request reconstruction.
No model/provider, hypothesis budgets, money limits, lifecycle or evidence
validation gates change. The complete archive retains all original evidence.

## Lossless representation before relevance filtering

Source query rows repeated file paths, hashes, sizes and other metadata for every
line. V5 factors identical fields into `common`, records the variable field names
in `columns`, and transmits ordered values in `rows` with encoding
`source_line_table_v1`. Merging common fields and each column/value row recreates
every original item. Line numbers, text and text-truncation flags remain intact.

Uniform database row results use `database_row_table_v1`: `common` contains item
metadata, and columns/rows reconstruct the original nested `row` dictionaries.
Actual scalar types, nulls, values and ordering are preserved. Nonuniform results
stay in their original representation; absent fields are never converted to null.
Query filters, snapshot origin, coverage, paging and truncation remain attached
to their original capture and evidence ID. No older findings or counterevidence
are removed. Source alias allocation remains the existing v4 allocation.

No additional LLM summary or call is used. Evidence recall/relevance filtering is
not needed for this lossless step and has not been introduced. This does not yet
solve the cost of resending large quantities of unique historical code.

## Source range behavior

Source reads retain the configurable maximum requested line count and reject
invalid/reversed/noninteger ranges. A valid bounded range crossing EOF returns
the available tail. A start past EOF returns an empty selected-lines result.
Results explicitly include total_lines, eof, requested bounds and actual returned
bounds (null for empty results). EOF is not truncation by a safety limit and does
not prove absence in other files or earlier portions of this file. Path and
pinned-Git-object safety checks are unchanged. Capture schema fields are additive
and optional for compatibility with existing captures.

New prompt guidance prioritizes targeted symbol/search/registration queries,
existing results and explicit EOF metadata over sequential whole-file reading.
It also asks the model to distinguish observation/deployment/capture/source times
and to preserve inconsistencies rather than invent an absent implementation.
There is no deterministic claim that a reported bug is fixed merely because code
exists in a newer snapshot.

## Offline measurement

`scripts/measure_investigation_context.py PACKAGE` reconstructs v4 and v5 requests
from stored contexts using PackageReader validation, checks that table decoding
exactly equals the original working view, and reports per-context character sizes.
It never calls a provider and does not modify the package. Stored contexts include
rejected/unused attempts; totals are not billed request counts or token estimates.

The Bug 17 archive's 14 contexts shrink from 1,961,028 to 1,017,342 user-message
characters (48.12%). Bug 20's nine contexts shrink from 563,131 to 549,750 (2.38%).
Every transformed view passes exact reconstruction. This difference is expected:
the former contains substantial repeated source-line metadata; the latter mostly
contains small database captures. Thus the earlier 70% reduction goal is not yet
met by this first safe step. Actual tokens, cost and reasoning quality need a
later live test; no paid experiments were run during implementation.