diff --git a/.claude/skills/audit-comet-expression/SKILL.md b/.claude/skills/audit-comet-expression/SKILL.md
index ab14ffe841..81327ecfc2 100644
--- a/.claude/skills/audit-comet-expression/SKILL.md
+++ b/.claude/skills/audit-comet-expression/SKILL.md
@@ -311,17 +311,44 @@ After implementing tests, tell the user how to run them:
 
 ---
 
-## Step 8: Update the Expression Audit Log
-
-After completing the audit (whether or not tests were added), append a row to the audit log at
-`docs/source/contributor-guide/expression-audit-log.md`.
+## Step 8: Update the Expression Manifest
+
+After completing the audit (whether or not tests were added), append an audit record to the
+matching expression in `dev/expressions.yml`.
+
+Locate the entry whose `name` matches the Spark SQL name for `$ARGUMENTS`. If the entry has no
+`audits:` key yet, add one. Append a new list item under `audits:` with:
+
+- `spark_versions` — the Spark versions checked, as a list of strings (e.g. `["3.4.3", "3.5.8", "4.0.1"]`)
+- `date` — today's date in `YYYY-MM-DD` format
+- `findings` — a folded block scalar (`>`) containing a brief summary: behavioral differences,
+  bugs found/fixed, tests added, known incompatibilities
+
+Audit records are ordered oldest-first within the list. If this is the expression's first audit,
+also flip `implemented: false` to `true` if the audit itself added the implementation.
+
+Example of a completed entry:
+
+```yaml
+- name: array_insert
+  category: array_funcs
+  implemented: true
+  audits:
+    - spark_versions: ["3.4.3", "3.5.8", "4.0.1"]
+      date: 2026-04-02
+      findings: >
+        No behavioral differences across Spark versions. Fixed `nullable()`
+        metadata bug (did not account for `pos_expr`). Added SQL tests for
+        multiple types, literal arguments, null handling, negative indices,
+        and multibyte UTF-8. Known incompatibility: pos=0 error message
+        differs from Spark's `INVALID_INDEX_OF_ZERO`.
+```
 
-The row should include:
+Verify the file still parses by running:
 
-- Expression name
-- Spark versions checked (e.g. 3.4.3, 3.5.8, 4.0.1)
-- Today's date
-- A brief summary of findings (behavioral differences, bugs found/fixed, tests added, known incompatibilities)
+```bash
+python3 -c "import yaml; yaml.safe_load(open('dev/expressions.yml'))"
+```
 
 ---
 
diff --git a/dev/expressions.yml b/dev/expressions.yml
new file mode 100644
index 0000000000..58ec0db6d7
--- /dev/null
+++ b/dev/expressions.yml
@@ -0,0 +1,1289 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# Source of truth for Spark expression coverage and audit status in Comet.
+# Phase 1: manually maintained. A future generator will consume this file.
+#
+# Fields:
+#   name         Spark SQL function name (lowercase, as in Spark FunctionRegistry)
+#   category     Spark FunctionRegistry category (agg_funcs, array_funcs, ...)
+#   implemented  true if the expression has a serde registered in Comet, else false
+#   audits       (optional) list of audit records, oldest first:
+#     spark_versions  list of Spark version strings audited against
+#     date            ISO date (YYYY-MM-DD) the audit was completed
+#     findings        free-text summary (may contain Markdown)
+
+expressions:
+  - name: any
+    category: agg_funcs
+    implemented: true
+  - name: any_value
+    category: agg_funcs
+    implemented: true
+  - name: approx_count_distinct
+    category: agg_funcs
+    implemented: false
+  - name: approx_percentile
+    category: agg_funcs
+    implemented: false
+  - name: array_agg
+    category: agg_funcs
+    implemented: false
+  - name: avg
+    category: agg_funcs
+    implemented: true
+  - name: bit_and
+    category: agg_funcs
+    implemented: true
+  - name: bit_or
+    category: agg_funcs
+    implemented: true
+  - name: bit_xor
+    category: agg_funcs
+    implemented: true
+  - name: bool_and
+    category: agg_funcs
+    implemented: true
+  - name: bool_or
+    category: agg_funcs
+    implemented: true
+  - name: collect_list
+    category: agg_funcs
+    implemented: false
+  - name: collect_set
+    category: agg_funcs
+    implemented: false
+  - name: corr
+    category: agg_funcs
+    implemented: false
+  - name: count
+    category: agg_funcs
+    implemented: true
+  - name: count_if
+    category: agg_funcs
+    implemented: true
+  - name: count_min_sketch
+    category: agg_funcs
+    implemented: false
+  - name: covar_pop
+    category: agg_funcs
+    implemented: true
+  - name: covar_samp
+    category: agg_funcs
+    implemented: true
+  - name: every
+    category: agg_funcs
+    implemented: true
+  - name: first
+    category: agg_funcs
+    implemented: true
+  - name: first_value
+    category: agg_funcs
+    implemented: true
+  - name: grouping
+    category: agg_funcs
+    implemented: false
+  - name: grouping_id
+    category: agg_funcs
+    implemented: false
+  - name: histogram_numeric
+    category: agg_funcs
+    implemented: false
+  - name: kurtosis
+    category: agg_funcs
+    implemented: false
+  - name: last
+    category: agg_funcs
+    implemented: true
+  - name: last_value
+    category: agg_funcs
+    implemented: true
+  - name: max
+    category: agg_funcs
+    implemented: true
+  - name: max_by
+    category: agg_funcs
+    implemented: false
+  - name: mean
+    category: agg_funcs
+    implemented: true
+  - name: median
+    category: agg_funcs
+    implemented: false
+  - name: min
+    category: agg_funcs
+    implemented: true
+  - name: min_by
+    category: agg_funcs
+    implemented: false
+  - name: mode
+    category: agg_funcs
+    implemented: false
+  - name: percentile
+    category: agg_funcs
+    implemented: false
+  - name: percentile_approx
+    category: agg_funcs
+    implemented: false
+  - name: regr_avgx
+    category: agg_funcs
+    implemented: true
+  - name: regr_avgy
+    category: agg_funcs
+    implemented: true
+  - name: regr_count
+    category: agg_funcs
+    implemented: true
+  - name: regr_intercept
+    category: agg_funcs
+    implemented: false
+  - name: regr_r2
+    category: agg_funcs
+    implemented: false
+  - name: regr_slope
+    category: agg_funcs
+    implemented: false
+  - name: regr_sxx
+    category: agg_funcs
+    implemented: false
+  - name: regr_sxy
+    category: agg_funcs
+    implemented: false
+  - name: regr_syy
+    category: agg_funcs
+    implemented: false
+  - name: skewness
+    category: agg_funcs
+    implemented: false
+  - name: some
+    category: agg_funcs
+    implemented: true
+  - name: std
+    category: agg_funcs
+    implemented: true
+  - name: stddev
+    category: agg_funcs
+    implemented: true
+  - name: stddev_pop
+    category: agg_funcs
+    implemented: true
+  - name: stddev_samp
+    category: agg_funcs
+    implemented: true
+  - name: sum
+    category: agg_funcs
+    implemented: true
+  - name: try_avg
+    category: agg_funcs
+    implemented: false
+  - name: try_sum
+    category: agg_funcs
+    implemented: false
+  - name: var_pop
+    category: agg_funcs
+    implemented: true
+  - name: var_samp
+    category: agg_funcs
+    implemented: true
+  - name: variance
+    category: agg_funcs
+    implemented: true
+  - name: array
+    category: array_funcs
+    implemented: true
+  - name: array_append
+    category: array_funcs
+    implemented: true
+  - name: array_compact
+    category: array_funcs
+    implemented: true
+  - name: array_contains
+    category: array_funcs
+    implemented: true
+  - name: array_distinct
+    category: array_funcs
+    implemented: true
+  - name: array_except
+    category: array_funcs
+    implemented: true
+  - name: array_insert
+    category: array_funcs
+    implemented: true
+    audits:
+      - spark_versions: ["3.4.3", "3.5.8", "4.0.1"]
+        date: 2026-04-02
+        findings: >
+          No behavioral differences across Spark versions. Fixed `nullable()`
+          metadata bug (did not account for `pos_expr`). Added SQL tests for
+          multiple types (string, boolean, double, float, long, short, byte),
+          literal arguments, null handling, negative indices, out-of-bounds
+          padding, special float values (NaN, Infinity), multibyte UTF-8, and
+          legacy negative index mode. Known incompatibility: pos=0 error
+          message differs from Spark's `INVALID_INDEX_OF_ZERO`.
+  - name: array_intersect
+    category: array_funcs
+    implemented: true
+  - name: array_join
+    category: array_funcs
+    implemented: true
+  - name: array_max
+    category: array_funcs
+    implemented: true
+  - name: array_min
+    category: array_funcs
+    implemented: false
+  - name: array_position
+    category: array_funcs
+    implemented: false
+  - name: array_remove
+    category: array_funcs
+    implemented: true
+  - name: array_repeat
+    category: array_funcs
+    implemented: true
+  - name: array_union
+    category: array_funcs
+    implemented: true
+  - name: arrays_overlap
+    category: array_funcs
+    implemented: true
+  - name: arrays_zip
+    category: array_funcs
+    implemented: false
+  - name: element_at
+    category: array_funcs
+    implemented: true
+  - name: flatten
+    category: array_funcs
+    implemented: false
+  - name: get
+    category: array_funcs
+    implemented: true
+  - name: sequence
+    category: array_funcs
+    implemented: false
+  - name: shuffle
+    category: array_funcs
+    implemented: false
+  - name: slice
+    category: array_funcs
+    implemented: false
+  - name: sort_array
+    category: array_funcs
+    implemented: true
+  - name: "&"
+    category: bitwise_funcs
+    implemented: true
+  - name: "^"
+    category: bitwise_funcs
+    implemented: true
+  - name: bit_count
+    category: bitwise_funcs
+    implemented: false
+  - name: bit_get
+    category: bitwise_funcs
+    implemented: false
+  - name: getbit
+    category: bitwise_funcs
+    implemented: false
+  - name: shiftright
+    category: bitwise_funcs
+    implemented: true
+  - name: shiftrightunsigned
+    category: bitwise_funcs
+    implemented: false
+  - name: "|"
+    category: bitwise_funcs
+    implemented: true
+  - name: "~"
+    category: bitwise_funcs
+    implemented: true
+  - name: array_size
+    category: collection_funcs
+    implemented: false
+  - name: cardinality
+    category: collection_funcs
+    implemented: false
+  - name: concat
+    category: collection_funcs
+    implemented: false
+  - name: reverse
+    category: collection_funcs
+    implemented: true
+  - name: size
+    category: collection_funcs
+    implemented: false
+  - name: coalesce
+    category: conditional_funcs
+    implemented: true
+  - name: if
+    category: conditional_funcs
+    implemented: true
+  - name: ifnull
+    category: conditional_funcs
+    implemented: true
+  - name: nanvl
+    category: conditional_funcs
+    implemented: false
+  - name: nullif
+    category: conditional_funcs
+    implemented: true
+  - name: nvl
+    category: conditional_funcs
+    implemented: true
+  - name: nvl2
+    category: conditional_funcs
+    implemented: true
+  - name: when
+    category: conditional_funcs
+    implemented: false
+  - name: bigint
+    category: conversion_funcs
+    implemented: false
+  - name: binary
+    category: conversion_funcs
+    implemented: false
+  - name: boolean
+    category: conversion_funcs
+    implemented: false
+  - name: cast
+    category: conversion_funcs
+    implemented: false
+  - name: date
+    category: conversion_funcs
+    implemented: false
+  - name: decimal
+    category: conversion_funcs
+    implemented: false
+  - name: double
+    category: conversion_funcs
+    implemented: false
+  - name: float
+    category: conversion_funcs
+    implemented: false
+  - name: int
+    category: conversion_funcs
+    implemented: false
+  - name: smallint
+    category: conversion_funcs
+    implemented: false
+  - name: string
+    category: conversion_funcs
+    implemented: false
+  - name: timestamp
+    category: conversion_funcs
+    implemented: false
+  - name: tinyint
+    category: conversion_funcs
+    implemented: false
+  - name: from_csv
+    category: csv_funcs
+    implemented: false
+  - name: schema_of_csv
+    category: csv_funcs
+    implemented: false
+  - name: to_csv
+    category: csv_funcs
+    implemented: false
+  - name: add_months
+    category: datetime_funcs
+    implemented: false
+  - name: convert_timezone
+    category: datetime_funcs
+    implemented: false
+  - name: curdate
+    category: datetime_funcs
+    implemented: true
+  - name: current_date
+    category: datetime_funcs
+    implemented: true
+  - name: current_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: current_timezone
+    category: datetime_funcs
+    implemented: true
+  - name: date_add
+    category: datetime_funcs
+    implemented: false
+  - name: date_diff
+    category: datetime_funcs
+    implemented: false
+  - name: date_format
+    category: datetime_funcs
+    implemented: false
+  - name: date_from_unix_date
+    category: datetime_funcs
+    implemented: true
+  - name: date_part
+    category: datetime_funcs
+    implemented: true
+  - name: date_sub
+    category: datetime_funcs
+    implemented: false
+  - name: date_trunc
+    category: datetime_funcs
+    implemented: false
+  - name: dateadd
+    category: datetime_funcs
+    implemented: false
+  - name: datediff
+    category: datetime_funcs
+    implemented: false
+  - name: datepart
+    category: datetime_funcs
+    implemented: true
+  - name: day
+    category: datetime_funcs
+    implemented: false
+  - name: dayofmonth
+    category: datetime_funcs
+    implemented: false
+  - name: dayofweek
+    category: datetime_funcs
+    implemented: false
+  - name: dayofyear
+    category: datetime_funcs
+    implemented: false
+  - name: extract
+    category: datetime_funcs
+    implemented: true
+  - name: from_unixtime
+    category: datetime_funcs
+    implemented: true
+  - name: from_utc_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: hour
+    category: datetime_funcs
+    implemented: false
+  - name: last_day
+    category: datetime_funcs
+    implemented: false
+  - name: localtimestamp
+    category: datetime_funcs
+    implemented: false
+  - name: make_date
+    category: datetime_funcs
+    implemented: false
+  - name: make_dt_interval
+    category: datetime_funcs
+    implemented: false
+  - name: make_interval
+    category: datetime_funcs
+    implemented: false
+  - name: make_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: make_timestamp_ltz
+    category: datetime_funcs
+    implemented: false
+  - name: make_timestamp_ntz
+    category: datetime_funcs
+    implemented: false
+  - name: make_ym_interval
+    category: datetime_funcs
+    implemented: false
+  - name: minute
+    category: datetime_funcs
+    implemented: false
+  - name: month
+    category: datetime_funcs
+    implemented: false
+  - name: months_between
+    category: datetime_funcs
+    implemented: false
+  - name: next_day
+    category: datetime_funcs
+    implemented: false
+  - name: now
+    category: datetime_funcs
+    implemented: false
+  - name: quarter
+    category: datetime_funcs
+    implemented: false
+  - name: second
+    category: datetime_funcs
+    implemented: false
+  - name: timestamp_micros
+    category: datetime_funcs
+    implemented: false
+  - name: timestamp_millis
+    category: datetime_funcs
+    implemented: false
+  - name: timestamp_seconds
+    category: datetime_funcs
+    implemented: false
+  - name: to_date
+    category: datetime_funcs
+    implemented: false
+  - name: to_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: to_timestamp_ltz
+    category: datetime_funcs
+    implemented: false
+  - name: to_timestamp_ntz
+    category: datetime_funcs
+    implemented: false
+  - name: to_unix_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: to_utc_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: trunc
+    category: datetime_funcs
+    implemented: false
+  - name: try_to_timestamp
+    category: datetime_funcs
+    implemented: false
+  - name: unix_date
+    category: datetime_funcs
+    implemented: false
+  - name: unix_micros
+    category: datetime_funcs
+    implemented: false
+  - name: unix_millis
+    category: datetime_funcs
+    implemented: false
+  - name: unix_seconds
+    category: datetime_funcs
+    implemented: false
+  - name: unix_timestamp
+    category: datetime_funcs
+    implemented: true
+  - name: weekday
+    category: datetime_funcs
+    implemented: false
+  - name: weekofyear
+    category: datetime_funcs
+    implemented: false
+  - name: year
+    category: datetime_funcs
+    implemented: false
+  - name: explode
+    category: generator_funcs
+    implemented: false
+  - name: explode_outer
+    category: generator_funcs
+    implemented: false
+  - name: inline
+    category: generator_funcs
+    implemented: false
+  - name: inline_outer
+    category: generator_funcs
+    implemented: false
+  - name: posexplode
+    category: generator_funcs
+    implemented: false
+  - name: posexplode_outer
+    category: generator_funcs
+    implemented: false
+  - name: stack
+    category: generator_funcs
+    implemented: false
+  - name: crc32
+    category: hash_funcs
+    implemented: true
+  - name: hash
+    category: hash_funcs
+    implemented: false
+  - name: md5
+    category: hash_funcs
+    implemented: true
+  - name: sha
+    category: hash_funcs
+    implemented: false
+  - name: sha1
+    category: hash_funcs
+    implemented: false
+  - name: sha2
+    category: hash_funcs
+    implemented: false
+  - name: xxhash64
+    category: hash_funcs
+    implemented: false
+  - name: from_json
+    category: json_funcs
+    implemented: false
+  - name: get_json_object
+    category: json_funcs
+    implemented: true
+  - name: json_array_length
+    category: json_funcs
+    implemented: false
+  - name: json_object_keys
+    category: json_funcs
+    implemented: false
+  - name: json_tuple
+    category: json_funcs
+    implemented: false
+  - name: schema_of_json
+    category: json_funcs
+    implemented: false
+  - name: to_json
+    category: json_funcs
+    implemented: false
+  - name: aggregate
+    category: lambda_funcs
+    implemented: false
+  - name: array_sort
+    category: lambda_funcs
+    implemented: false
+  - name: exists
+    category: lambda_funcs
+    implemented: false
+  - name: filter
+    category: lambda_funcs
+    implemented: false
+  - name: forall
+    category: lambda_funcs
+    implemented: false
+  - name: map_filter
+    category: lambda_funcs
+    implemented: false
+  - name: map_zip_with
+    category: lambda_funcs
+    implemented: false
+  - name: reduce
+    category: lambda_funcs
+    implemented: false
+  - name: transform
+    category: lambda_funcs
+    implemented: false
+  - name: transform_keys
+    category: lambda_funcs
+    implemented: false
+  - name: transform_values
+    category: lambda_funcs
+    implemented: false
+  - name: zip_with
+    category: lambda_funcs
+    implemented: false
+  - name: element_at
+    category: map_funcs
+    implemented: false
+  - name: map
+    category: map_funcs
+    implemented: false
+  - name: map_concat
+    category: map_funcs
+    implemented: false
+  - name: map_contains_key
+    category: map_funcs
+    implemented: true
+  - name: map_entries
+    category: map_funcs
+    implemented: false
+  - name: map_from_arrays
+    category: map_funcs
+    implemented: false
+  - name: map_from_entries
+    category: map_funcs
+    implemented: false
+  - name: map_keys
+    category: map_funcs
+    implemented: true
+  - name: map_values
+    category: map_funcs
+    implemented: false
+  - name: str_to_map
+    category: map_funcs
+    implemented: false
+  - name: try_element_at
+    category: map_funcs
+    implemented: false
+  - name: "%"
+    category: math_funcs
+    implemented: true
+  - name: "-"
+    category: math_funcs
+    implemented: true
+  - name: "-"
+    category: math_funcs
+    implemented: true
+  - name: "-"
+    category: math_funcs
+    implemented: true
+  - name: "/"
+    category: math_funcs
+    implemented: true
+  - name: abs
+    category: math_funcs
+    implemented: true
+  - name: acos
+    category: math_funcs
+    implemented: true
+  - name: acosh
+    category: math_funcs
+    implemented: false
+  - name: asin
+    category: math_funcs
+    implemented: true
+  - name: asinh
+    category: math_funcs
+    implemented: false
+  - name: atan
+    category: math_funcs
+    implemented: true
+  - name: atan2
+    category: math_funcs
+    implemented: true
+  - name: atanh
+    category: math_funcs
+    implemented: false
+  - name: bin
+    category: math_funcs
+    implemented: true
+  - name: bround
+    category: math_funcs
+    implemented: false
+  - name: cbrt
+    category: math_funcs
+    implemented: false
+  - name: ceil
+    category: math_funcs
+    implemented: true
+  - name: ceiling
+    category: math_funcs
+    implemented: true
+  - name: conv
+    category: math_funcs
+    implemented: false
+  - name: cos
+    category: math_funcs
+    implemented: true
+  - name: cosh
+    category: math_funcs
+    implemented: false
+  - name: cot
+    category: math_funcs
+    implemented: false
+  - name: csc
+    category: math_funcs
+    implemented: false
+  - name: degrees
+    category: math_funcs
+    implemented: false
+  - name: div
+    category: math_funcs
+    implemented: false
+  - name: e
+    category: math_funcs
+    implemented: false
+  - name: exp
+    category: math_funcs
+    implemented: true
+  - name: expm1
+    category: math_funcs
+    implemented: false
+  - name: factorial
+    category: math_funcs
+    implemented: false
+  - name: floor
+    category: math_funcs
+    implemented: true
+  - name: greatest
+    category: math_funcs
+    implemented: false
+  - name: hex
+    category: math_funcs
+    implemented: false
+  - name: hypot
+    category: math_funcs
+    implemented: false
+  - name: least
+    category: math_funcs
+    implemented: false
+  - name: ln
+    category: math_funcs
+    implemented: true
+  - name: log
+    category: math_funcs
+    implemented: false
+  - name: log10
+    category: math_funcs
+    implemented: true
+  - name: log1p
+    category: math_funcs
+    implemented: false
+  - name: log2
+    category: math_funcs
+    implemented: true
+  - name: mod
+    category: math_funcs
+    implemented: true
+  - name: negative
+    category: math_funcs
+    implemented: true
+  - name: pi
+    category: math_funcs
+    implemented: false
+  - name: pmod
+    category: math_funcs
+    implemented: false
+  - name: positive
+    category: math_funcs
+    implemented: true
+  - name: pow
+    category: math_funcs
+    implemented: true
+  - name: power
+    category: math_funcs
+    implemented: true
+  - name: radians
+    category: math_funcs
+    implemented: false
+  - name: rand
+    category: math_funcs
+    implemented: false
+  - name: randn
+    category: math_funcs
+    implemented: false
+  - name: random
+    category: math_funcs
+    implemented: false
+  - name: rint
+    category: math_funcs
+    implemented: false
+  - name: round
+    category: math_funcs
+    implemented: true
+  - name: sec
+    category: math_funcs
+    implemented: false
+  - name: shiftleft
+    category: math_funcs
+    implemented: true
+  - name: sign
+    category: math_funcs
+    implemented: true
+  - name: signum
+    category: math_funcs
+    implemented: true
+  - name: sin
+    category: math_funcs
+    implemented: true
+  - name: sinh
+    category: math_funcs
+    implemented: false
+  - name: sqrt
+    category: math_funcs
+    implemented: true
+  - name: tan
+    category: math_funcs
+    implemented: true
+  - name: tanh
+    category: math_funcs
+    implemented: false
+  - name: try_add
+    category: math_funcs
+    implemented: true
+  - name: try_divide
+    category: math_funcs
+    implemented: true
+  - name: try_multiply
+    category: math_funcs
+    implemented: true
+  - name: try_subtract
+    category: math_funcs
+    implemented: true
+  - name: unhex
+    category: math_funcs
+    implemented: true
+  - name: width_bucket
+    category: math_funcs
+    implemented: true
+  - name: aes_decrypt
+    category: misc_funcs
+    implemented: false
+  - name: aes_encrypt
+    category: misc_funcs
+    implemented: false
+  - name: assert_true
+    category: misc_funcs
+    implemented: false
+  - name: current_catalog
+    category: misc_funcs
+    implemented: true
+  - name: current_database
+    category: misc_funcs
+    implemented: true
+  - name: current_schema
+    category: misc_funcs
+    implemented: true
+  - name: current_user
+    category: misc_funcs
+    implemented: true
+  - name: equal_null
+    category: misc_funcs
+    implemented: true
+  - name: input_file_block_length
+    category: misc_funcs
+    implemented: false
+  - name: input_file_block_start
+    category: misc_funcs
+    implemented: false
+  - name: input_file_name
+    category: misc_funcs
+    implemented: false
+  - name: monotonically_increasing_id
+    category: misc_funcs
+    implemented: true
+  - name: raise_error
+    category: misc_funcs
+    implemented: false
+  - name: rand
+    category: misc_funcs
+    implemented: true
+  - name: randn
+    category: misc_funcs
+    implemented: true
+  - name: spark_partition_id
+    category: misc_funcs
+    implemented: true
+  - name: typeof
+    category: misc_funcs
+    implemented: false
+  - name: user
+    category: misc_funcs
+    implemented: true
+  - name: uuid
+    category: misc_funcs
+    implemented: false
+  - name: version
+    category: misc_funcs
+    implemented: false
+  - name: "!"
+    category: predicate_funcs
+    implemented: true
+  - name: "<"
+    category: predicate_funcs
+    implemented: true
+  - name: "<="
+    category: predicate_funcs
+    implemented: true
+  - name: "<=>"
+    category: predicate_funcs
+    implemented: true
+  - name: "="
+    category: predicate_funcs
+    implemented: true
+  - name: "=="
+    category: predicate_funcs
+    implemented: true
+  - name: ">"
+    category: predicate_funcs
+    implemented: true
+  - name: "> ="
+    category: predicate_funcs
+    implemented: true
+  - name: and
+    category: predicate_funcs
+    implemented: true
+  - name: ilike
+    category: predicate_funcs
+    implemented: true
+  - name: in
+    category: predicate_funcs
+    implemented: true
+  - name: isnan
+    category: predicate_funcs
+    implemented: false
+  - name: isnotnull
+    category: predicate_funcs
+    implemented: true
+  - name: isnull
+    category: predicate_funcs
+    implemented: true
+  - name: like
+    category: predicate_funcs
+    implemented: true
+  - name: not
+    category: predicate_funcs
+    implemented: true
+  - name: or
+    category: predicate_funcs
+    implemented: true
+  - name: regexp
+    category: predicate_funcs
+    implemented: false
+  - name: regexp_like
+    category: predicate_funcs
+    implemented: false
+  - name: rlike
+    category: predicate_funcs
+    implemented: false
+  - name: ascii
+    category: string_funcs
+    implemented: true
+  - name: base64
+    category: string_funcs
+    implemented: false
+  - name: bit_length
+    category: string_funcs
+    implemented: true
+  - name: btrim
+    category: string_funcs
+    implemented: true
+  - name: char
+    category: string_funcs
+    implemented: true
+  - name: char_length
+    category: string_funcs
+    implemented: true
+  - name: character_length
+    category: string_funcs
+    implemented: true
+  - name: chr
+    category: string_funcs
+    implemented: true
+  - name: concat_ws
+    category: string_funcs
+    implemented: true
+  - name: contains
+    category: string_funcs
+    implemented: true
+  - name: decode
+    category: string_funcs
+    implemented: false
+  - name: elt
+    category: string_funcs
+    implemented: false
+  - name: encode
+    category: string_funcs
+    implemented: false
+  - name: endswith
+    category: string_funcs
+    implemented: true
+  - name: find_in_set
+    category: string_funcs
+    implemented: false
+  - name: format_number
+    category: string_funcs
+    implemented: false
+  - name: format_string
+    category: string_funcs
+    implemented: false
+  - name: initcap
+    category: string_funcs
+    implemented: true
+  - name: instr
+    category: string_funcs
+    implemented: true
+  - name: lcase
+    category: string_funcs
+    implemented: true
+  - name: left
+    category: string_funcs
+    implemented: false
+  - name: len
+    category: string_funcs
+    implemented: true
+  - name: length
+    category: string_funcs
+    implemented: true
+  - name: levenshtein
+    category: string_funcs
+    implemented: false
+  - name: locate
+    category: string_funcs
+    implemented: false
+  - name: lower
+    category: string_funcs
+    implemented: true
+  - name: lpad
+    category: string_funcs
+    implemented: true
+  - name: ltrim
+    category: string_funcs
+    implemented: true
+  - name: mask
+    category: string_funcs
+    implemented: false
+  - name: octet_length
+    category: string_funcs
+    implemented: true
+  - name: overlay
+    category: string_funcs
+    implemented: false
+  - name: position
+    category: string_funcs
+    implemented: false
+  - name: printf
+    category: string_funcs
+    implemented: false
+  - name: regexp_count
+    category: string_funcs
+    implemented: false
+  - name: regexp_extract
+    category: string_funcs
+    implemented: false
+  - name: regexp_extract_all
+    category: string_funcs
+    implemented: false
+  - name: regexp_instr
+    category: string_funcs
+    implemented: false
+  - name: regexp_replace
+    category: string_funcs
+    implemented: false
+  - name: regexp_substr
+    category: string_funcs
+    implemented: false
+  - name: repeat
+    category: string_funcs
+    implemented: true
+  - name: replace
+    category: string_funcs
+    implemented: true
+  - name: right
+    category: string_funcs
+    implemented: false
+  - name: rpad
+    category: string_funcs
+    implemented: true
+  - name: rtrim
+    category: string_funcs
+    implemented: true
+  - name: sentences
+    category: string_funcs
+    implemented: false
+  - name: soundex
+    category: string_funcs
+    implemented: false
+  - name: space
+    category: string_funcs
+    implemented: true
+  - name: split
+    category: string_funcs
+    implemented: false
+  - name: split_part
+    category: string_funcs
+    implemented: false
+  - name: startswith
+    category: string_funcs
+    implemented: true
+  - name: substr
+    category: string_funcs
+    implemented: false
+  - name: substring
+    category: string_funcs
+    implemented: false
+  - name: substring_index
+    category: string_funcs
+    implemented: false
+  - name: to_binary
+    category: string_funcs
+    implemented: false
+  - name: to_char
+    category: string_funcs
+    implemented: false
+  - name: to_number
+    category: string_funcs
+    implemented: false
+  - name: translate
+    category: string_funcs
+    implemented: true
+  - name: trim
+    category: string_funcs
+    implemented: true
+  - name: try_to_binary
+    category: string_funcs
+    implemented: false
+  - name: try_to_number
+    category: string_funcs
+    implemented: false
+  - name: ucase
+    category: string_funcs
+    implemented: true
+  - name: unbase64
+    category: string_funcs
+    implemented: false
+  - name: upper
+    category: string_funcs
+    implemented: true
+  - name: named_struct
+    category: struct_funcs
+    implemented: false
+  - name: struct
+    category: struct_funcs
+    implemented: false
+  - name: parse_url
+    category: url_funcs
+    implemented: false
+  - name: url_decode
+    category: url_funcs
+    implemented: false
+  - name: url_encode
+    category: url_funcs
+    implemented: false
+  - name: cume_dist
+    category: window_funcs
+    implemented: false
+  - name: dense_rank
+    category: window_funcs
+    implemented: false
+  - name: lag
+    category: window_funcs
+    implemented: false
+  - name: lead
+    category: window_funcs
+    implemented: false
+  - name: nth_value
+    category: window_funcs
+    implemented: false
+  - name: ntile
+    category: window_funcs
+    implemented: false
+  - name: percent_rank
+    category: window_funcs
+    implemented: false
+  - name: rank
+    category: window_funcs
+    implemented: false
+  - name: row_number
+    category: window_funcs
+    implemented: false
+  - name: xpath
+    category: xml_funcs
+    implemented: false
+  - name: xpath_boolean
+    category: xml_funcs
+    implemented: false
+  - name: xpath_double
+    category: xml_funcs
+    implemented: false
+  - name: xpath_float
+    category: xml_funcs
+    implemented: false
+  - name: xpath_int
+    category: xml_funcs
+    implemented: false
+  - name: xpath_long
+    category: xml_funcs
+    implemented: false
+  - name: xpath_number
+    category: xml_funcs
+    implemented: false
+  - name: xpath_short
+    category: xml_funcs
+    implemented: false
+  - name: xpath_string
+    category: xml_funcs
+    implemented: false
diff --git a/docs/source/contributor-guide/adding_a_new_expression.md b/docs/source/contributor-guide/adding_a_new_expression.md
index 10af50e069..0002d7f1c0 100644
--- a/docs/source/contributor-guide/adding_a_new_expression.md
+++ b/docs/source/contributor-guide/adding_a_new_expression.md
@@ -25,7 +25,7 @@ Before you start, have a look through [these slides](https://docs.google.com/pre
 
 ## Finding an Expression to Add
 
-You may have a specific expression in mind that you'd like to add, but if not, you can review the [expression coverage document](https://github.com/apache/datafusion-comet/blob/main/docs/spark_expressions_support.md) to see which expressions are not yet supported.
+You may have a specific expression in mind that you'd like to add, but if not, you can review the [expression manifest](https://github.com/apache/datafusion-comet/blob/main/dev/expressions.yml) to see which expressions are not yet supported. Entries with `implemented: false` are candidates for new work.
 
 ## Implementing the Expression
 
diff --git a/docs/source/contributor-guide/expression-audit-log.md b/docs/source/contributor-guide/expression-audit-log.md
deleted file mode 100644
index 088e4ea766..0000000000
--- a/docs/source/contributor-guide/expression-audit-log.md
+++ /dev/null
@@ -1,32 +0,0 @@
-<!--
-Licensed to the Apache Software Foundation (ASF) under one
-or more contributor license agreements.  See the NOTICE file
-distributed with this work for additional information
-regarding copyright ownership.  The ASF licenses this file
-to you under the Apache License, Version 2.0 (the
-"License"); you may not use this file except in compliance
-with the License.  You may obtain a copy of the License at
-
-  http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing,
-software distributed under the License is distributed on an
-"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-KIND, either express or implied.  See the License for the
-specific language governing permissions and limitations
-under the License.
--->
-
-# Expression Audit Log
-
-This document tracks which Comet expressions have been audited against their Spark
-implementations for correctness and test coverage.
-
-Each audit compares the Comet implementation against the Spark source code for the listed
-versions, reviews existing test coverage, identifies gaps, and adds missing tests where needed.
-
-## Audited Expressions
-
-| Expression     | Spark Versions Checked | Date       | Findings                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
-| -------------- | ---------------------- | ---------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `array_insert` | 3.4.3, 3.5.8, 4.0.1    | 2026-04-02 | No behavioral differences across Spark versions. Fixed `nullable()` metadata bug (did not account for `pos_expr`). Added SQL tests for multiple types (string, boolean, double, float, long, short, byte), literal arguments, null handling, negative indices, out-of-bounds padding, special float values (NaN, Infinity), multibyte UTF-8, and legacy negative index mode. Known incompatibility: pos=0 error message differs from Spark's `INVALID_INDEX_OF_ZERO`. |
diff --git a/docs/spark_expressions_support.md b/docs/spark_expressions_support.md
deleted file mode 100644
index 9d9e8f7017..0000000000
--- a/docs/spark_expressions_support.md
+++ /dev/null
@@ -1,499 +0,0 @@
-<!---
-  Licensed to the Apache Software Foundation (ASF) under one
-  or more contributor license agreements.  See the NOTICE file
-  distributed with this work for additional information
-  regarding copyright ownership.  The ASF licenses this file
-  to you under the Apache License, Version 2.0 (the
-  "License"); you may not use this file except in compliance
-  with the License.  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing,
-  software distributed under the License is distributed on an
-  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-  KIND, either express or implied.  See the License for the
-  specific language governing permissions and limitations
-  under the License.
--->
-
-# Supported Spark Expressions
-
-### agg_funcs
-
-- [x] any
-- [x] any_value
-- [ ] approx_count_distinct
-- [ ] approx_percentile
-- [ ] array_agg
-- [x] avg
-- [x] bit_and
-- [x] bit_or
-- [x] bit_xor
-- [x] bool_and
-- [x] bool_or
-- [ ] collect_list
-- [ ] collect_set
-- [ ] corr
-- [x] count
-- [x] count_if
-- [ ] count_min_sketch
-- [x] covar_pop
-- [x] covar_samp
-- [x] every
-- [x] first
-- [x] first_value
-- [ ] grouping
-- [ ] grouping_id
-- [ ] histogram_numeric
-- [ ] kurtosis
-- [x] last
-- [x] last_value
-- [x] max
-- [ ] max_by
-- [x] mean
-- [ ] median
-- [x] min
-- [ ] min_by
-- [ ] mode
-- [ ] percentile
-- [ ] percentile_approx
-- [x] regr_avgx
-- [x] regr_avgy
-- [x] regr_count
-- [ ] regr_intercept
-- [ ] regr_r2
-- [ ] regr_slope
-- [ ] regr_sxx
-- [ ] regr_sxy
-- [ ] regr_syy
-- [ ] skewness
-- [x] some
-- [x] std
-- [x] stddev
-- [x] stddev_pop
-- [x] stddev_samp
-- [x] sum
-- [ ] try_avg
-- [ ] try_sum
-- [x] var_pop
-- [x] var_samp
-- [x] variance
-
-### array_funcs
-
-- [x] array
-- [x] array_append
-- [x] array_compact
-- [x] array_contains
-- [x] array_distinct
-- [x] array_except
-- [x] array_insert
-- [x] array_intersect
-- [x] array_join
-- [x] array_max
-- [ ] array_min
-- [ ] array_position
-- [x] array_remove
-- [x] array_repeat
-- [x] array_union
-- [x] arrays_overlap
-- [ ] arrays_zip
-- [x] element_at
-- [ ] flatten
-- [x] get
-- [ ] sequence
-- [ ] shuffle
-- [ ] slice
-- [x] sort_array
-
-### bitwise_funcs
-
-- [x] &
-- [x] ^
-- [ ] bit_count
-- [ ] bit_get
-- [ ] getbit
-- [x] shiftright
-- [ ] shiftrightunsigned
-- [x] |
-- [x] ~
-
-### collection_funcs
-
-- [ ] array_size
-- [ ] cardinality
-- [ ] concat
-- [x] reverse
-- [ ] size
-
-### conditional_funcs
-
-- [x] coalesce
-- [x] if
-- [x] ifnull
-- [ ] nanvl
-- [x] nullif
-- [x] nvl
-- [x] nvl2
-- [ ] when
-
-### conversion_funcs
-
-- [ ] bigint
-- [ ] binary
-- [ ] boolean
-- [ ] cast
-- [ ] date
-- [ ] decimal
-- [ ] double
-- [ ] float
-- [ ] int
-- [ ] smallint
-- [ ] string
-- [ ] timestamp
-- [ ] tinyint
-
-### csv_funcs
-
-- [ ] from_csv
-- [ ] schema_of_csv
-- [ ] to_csv
-
-### datetime_funcs
-
-- [ ] add_months
-- [ ] convert_timezone
-- [x] curdate
-- [x] current_date
-- [ ] current_timestamp
-- [x] current_timezone
-- [ ] date_add
-- [ ] date_diff
-- [ ] date_format
-- [x] date_from_unix_date
-- [x] date_part
-- [ ] date_sub
-- [ ] date_trunc
-- [ ] dateadd
-- [ ] datediff
-- [x] datepart
-- [ ] day
-- [ ] dayofmonth
-- [ ] dayofweek
-- [ ] dayofyear
-- [x] extract
-- [x] from_unixtime
-- [ ] from_utc_timestamp
-- [ ] hour
-- [ ] last_day
-- [ ] localtimestamp
-- [ ] make_date
-- [ ] make_dt_interval
-- [ ] make_interval
-- [ ] make_timestamp
-- [ ] make_timestamp_ltz
-- [ ] make_timestamp_ntz
-- [ ] make_ym_interval
-- [ ] minute
-- [ ] month
-- [ ] months_between
-- [ ] next_day
-- [ ] now
-- [ ] quarter
-- [ ] second
-- [ ] timestamp_micros
-- [ ] timestamp_millis
-- [ ] timestamp_seconds
-- [ ] to_date
-- [ ] to_timestamp
-- [ ] to_timestamp_ltz
-- [ ] to_timestamp_ntz
-- [ ] to_unix_timestamp
-- [ ] to_utc_timestamp
-- [ ] trunc
-- [ ] try_to_timestamp
-- [ ] unix_date
-- [ ] unix_micros
-- [ ] unix_millis
-- [ ] unix_seconds
-- [x] unix_timestamp
-- [ ] weekday
-- [ ] weekofyear
-- [ ] year
-
-### generator_funcs
-
-- [ ] explode
-- [ ] explode_outer
-- [ ] inline
-- [ ] inline_outer
-- [ ] posexplode
-- [ ] posexplode_outer
-- [ ] stack
-
-### hash_funcs
-
-- [x] crc32
-- [ ] hash
-- [x] md5
-- [ ] sha
-- [ ] sha1
-- [ ] sha2
-- [ ] xxhash64
-
-### json_funcs
-
-- [ ] from_json
-- [x] get_json_object
-- [ ] json_array_length
-- [ ] json_object_keys
-- [ ] json_tuple
-- [ ] schema_of_json
-- [ ] to_json
-
-### lambda_funcs
-
-- [ ] aggregate
-- [ ] array_sort
-- [ ] exists
-- [ ] filter
-- [ ] forall
-- [ ] map_filter
-- [ ] map_zip_with
-- [ ] reduce
-- [ ] transform
-- [ ] transform_keys
-- [ ] transform_values
-- [ ] zip_with
-
-### map_funcs
-
-- [ ] element_at
-- [ ] map
-- [ ] map_concat
-- [x] map_contains_key
-- [ ] map_entries
-- [ ] map_from_arrays
-- [ ] map_from_entries
-- [x] map_keys
-- [ ] map_values
-- [ ] str_to_map
-- [ ] try_element_at
-
-### math_funcs
-
-- [x] %
-- [x] -
-- [x] -
-- [x] -
-- [x] /
-- [x] abs
-- [x] acos
-- [ ] acosh
-- [x] asin
-- [ ] asinh
-- [x] atan
-- [x] atan2
-- [ ] atanh
-- [x] bin
-- [ ] bround
-- [ ] cbrt
-- [x] ceil
-- [x] ceiling
-- [ ] conv
-- [x] cos
-- [ ] cosh
-- [ ] cot
-- [ ] csc
-- [ ] degrees
-- [ ] div
-- [ ] e
-- [x] exp
-- [ ] expm1
-- [ ] factorial
-- [x] floor
-- [ ] greatest
-- [ ] hex
-- [ ] hypot
-- [ ] least
-- [x] ln
-- [ ] log
-- [x] log10
-- [ ] log1p
-- [x] log2
-- [x] mod
-- [x] negative
-- [ ] pi
-- [ ] pmod
-- [x] positive
-- [x] pow
-- [x] power
-- [ ] radians
-- [ ] rand
-- [ ] randn
-- [ ] random
-- [ ] rint
-- [x] round
-- [ ] sec
-- [x] shiftleft
-- [x] sign
-- [x] signum
-- [x] sin
-- [ ] sinh
-- [x] sqrt
-- [x] tan
-- [ ] tanh
-- [x] try_add
-- [x] try_divide
-- [x] try_multiply
-- [x] try_subtract
-- [x] unhex
-- [x] width_bucket
-
-### misc_funcs
-
-- [ ] aes_decrypt
-- [ ] aes_encrypt
-- [ ] assert_true
-- [x] current_catalog
-- [x] current_database
-- [x] current_schema
-- [x] current_user
-- [x] equal_null
-- [ ] input_file_block_length
-- [ ] input_file_block_start
-- [ ] input_file_name
-- [x] monotonically_increasing_id
-- [ ] raise_error
-- [x] rand
-- [x] randn
-- [x] spark_partition_id
-- [ ] typeof
-- [x] user
-- [ ] uuid
-- [ ] version
-
-### predicate_funcs
-
-- [x] !
-- [x] <
-- [x] <=
-- [x] <=>
-- [x] =
-- [x] ==
-- [x] >
-- [x] > =
-- [x] and
-- [x] ilike
-- [x] in
-- [ ] isnan
-- [x] isnotnull
-- [x] isnull
-- [x] like
-- [x] not
-- [x] or
-- [ ] regexp
-- [ ] regexp_like
-- [ ] rlike
-
-### string_funcs
-
-- [x] ascii
-- [ ] base64
-- [x] bit_length
-- [x] btrim
-- [x] char
-- [x] char_length
-- [x] character_length
-- [x] chr
-- [x] concat_ws
-- [x] contains
-- [ ] decode
-- [ ] elt
-- [ ] encode
-- [x] endswith
-- [ ] find_in_set
-- [ ] format_number
-- [ ] format_string
-- [x] initcap
-- [x] instr
-- [x] lcase
-- [ ] left
-- [x] len
-- [x] length
-- [ ] levenshtein
-- [ ] locate
-- [x] lower
-- [x] lpad
-- [x] ltrim
-- [ ] mask
-- [x] octet_length
-- [ ] overlay
-- [ ] position
-- [ ] printf
-- [ ] regexp_count
-- [ ] regexp_extract
-- [ ] regexp_extract_all
-- [ ] regexp_instr
-- [ ] regexp_replace
-- [ ] regexp_substr
-- [x] repeat
-- [x] replace
-- [ ] right
-- [x] rpad
-- [x] rtrim
-- [ ] sentences
-- [ ] soundex
-- [x] space
-- [ ] split
-- [ ] split_part
-- [x] startswith
-- [ ] substr
-- [ ] substring
-- [ ] substring_index
-- [ ] to_binary
-- [ ] to_char
-- [ ] to_number
-- [x] translate
-- [x] trim
-- [ ] try_to_binary
-- [ ] try_to_number
-- [x] ucase
-- [ ] unbase64
-- [x] upper
-
-### struct_funcs
-
-- [ ] named_struct
-- [ ] struct
-
-### url_funcs
-
-- [ ] parse_url
-- [ ] url_decode
-- [ ] url_encode
-
-### window_funcs
-
-- [ ] cume_dist
-- [ ] dense_rank
-- [ ] lag
-- [ ] lead
-- [ ] nth_value
-- [ ] ntile
-- [ ] percent_rank
-- [ ] rank
-- [ ] row_number
-
-### xml_funcs
-
-- [ ] xpath
-- [ ] xpath_boolean
-- [ ] xpath_double
-- [ ] xpath_float
-- [ ] xpath_int
-- [ ] xpath_long
-- [ ] xpath_number
-- [ ] xpath_short
-- [ ] xpath_string