Case 410
The lesson was filed where nobody looks - 3 of 7 places reach the person who needs it
the_lesson_was_filed_where_nobody_looks.eml scores each place a lesson can live by the same three properties and computes the reach rather than arguing it.
ok: true — round-trip fixpoint reached (python1 == python2)updated 2026-08-16
EML
eml# Self-authored for the EML case corpus (no external origin). The document is
# correct, findable, and read by nobody at the moment it would help.
#
# Writing it down is the recommendation every postmortem ends with, and the
# document that follows is genuinely good: accurate, specific, and indexed.
# Someone searching for it will find it.
#
# Searching for it requires knowing it exists, and the people who hit this
# problem are by definition the ones who did not know. So the question is not
# whether the lesson was recorded - it was - but whether the recording is on
# the path anyone walks when the situation arises.
#
# Each place a lesson can live is scored by the same three properties, and the
# reach is computed from them rather than argued.
# [place, is it read at the moment of need, does it require knowing it exists, does it survive staff turnover]
[["a wiki page", 0, 1, 1], ["the postmortem document", 0, 1, 1], ["a team chat message", 0, 0, 0], ["onboarding training", 0, 1, 0], ["a comment at the call site", 1, 0, 1], ["a test that fails", 1, 0, 1], ["a lint rule", 1, 0, 1]] => places
def reaches(p):
if p[1] == 0:
return 0
if p[2] == 1:
return 0
return 1
"places a lesson can be filed : " + str(len(places)) ^0
"" ^0
"place at the moment needs prior knowledge survives turnover reaches" ^0
for p in places:
"" => l
if p[1] == 1:
l + "yes" => l
else:
l + "no " => l
"" => m
if p[2] == 1:
m + "yes" => m
else:
m + "no " => m
"" => n
if p[3] == 1:
n + "yes" => n
else:
n + "no " => n
"" => r
if reaches(p) == 1:
r + "YES" => r
else:
r + "no" => r
" " + p[0] + " " + l + " " + m + " " + n + " " + r ^0
"" ^0
0 => reaching
for p in places:
reaching + reaches(p) => reaching
" places that reach the person who needs it : " + str(reaching) + " of " + str(len(places)) ^0
"" ^0
# ---- what the ones that fail have in common ----
"the ones that do not reach" ^0
0 => not_at_moment
0 => needs_knowing
for p in places:
if reaches(p) == 0:
if p[1] == 0:
not_at_moment + 1 => not_at_moment
else:
needs_knowing + 1 => needs_knowing
" " + p[0] ^0
" not present at the moment of need : " + str(not_at_moment) ^0
" present but require knowing to look : " + str(needs_knowing) ^0
"" ^0
# ---- the ones that reach, and what they have in common ----
"the ones that reach" ^0
for p in places:
if reaches(p) == 1:
" " + p[0] ^0
" all three are in the path of the work, not in a description of it" ^0
"" ^0
# ---- turnover ----
#
# Surviving turnover is a separate property from reaching. A chat message
# reaches nobody later AND does not survive; a wiki page survives and still
# does not reach.
0 => survive
0 => survive_and_reach
for p in places:
survive + p[3] => survive
if p[3] == 1:
survive_and_reach + reaches(p) => survive_and_reach
"durability against reach" ^0
" survive turnover : " + str(survive) + " of " + str(len(places)) ^0
" survive AND reach : " + str(survive_and_reach) ^0
" survive and do NOT reach: " + str(survive - survive_and_reach) ^0
if survive > survive_and_reach:
" a lesson can be permanent and still never arrive" ^0
"" ^0
# ---- the control: a reader who already knows the lesson exists ----
#
# For them every place works. The document is not badly written; it is
# addressed to someone who does not need it.
0 => informed_reach
for p in places:
if p[1] == 1:
informed_reach + 1 => informed_reach
else:
informed_reach + 1 => informed_reach
"control - a reader who already knows the lesson exists" ^0
" places they can use : " + str(informed_reach) + " of " + str(len(places)) ^0
" which is why the document passes review" ^0
"" ^0
"The lesson was recorded and the recording is correct. Whether it is on the" ^0
"path the next person walks is a property of the place, and the place is" ^0
"chosen by whoever writes the postmortem rather than by whoever needs it." ^0Python (deterministic transpilation)
pythonplaces = [["a wiki page", 0, 1, 1], ["the postmortem document", 0, 1, 1], ["a team chat message", 0, 0, 0], ["onboarding training", 0, 1, 0], ["a comment at the call site", 1, 0, 1], ["a test that fails", 1, 0, 1], ["a lint rule", 1, 0, 1]]
def reaches(p):
if p[1] == 0:
return 0
if p[2] == 1:
return 0
return 1
print("places a lesson can be filed : " + str(len(places)))
print("")
print("place at the moment needs prior knowledge survives turnover reaches")
for p in places:
l = ""
if p[1] == 1:
l = l + "yes"
else:
l = l + "no "
m = ""
if p[2] == 1:
m = m + "yes"
else:
m = m + "no "
n = ""
if p[3] == 1:
n = n + "yes"
else:
n = n + "no "
r = ""
if reaches(p) == 1:
r = r + "YES"
else:
r = r + "no"
print(" " + p[0] + " " + l + " " + m + " " + n + " " + r)
print("")
reaching = 0
for p in places:
reaching = reaching + reaches(p)
print(" places that reach the person who needs it : " + str(reaching) + " of " + str(len(places)))
print("")
print("the ones that do not reach")
not_at_moment = 0
needs_knowing = 0
for p in places:
if reaches(p) == 0:
if p[1] == 0:
not_at_moment = not_at_moment + 1
else:
needs_knowing = needs_knowing + 1
print(" " + p[0])
print(" not present at the moment of need : " + str(not_at_moment))
print(" present but require knowing to look : " + str(needs_knowing))
print("")
print("the ones that reach")
for p in places:
if reaches(p) == 1:
print(" " + p[0])
print(" all three are in the path of the work, not in a description of it")
print("")
survive = 0
survive_and_reach = 0
for p in places:
survive = survive + p[3]
if p[3] == 1:
survive_and_reach = survive_and_reach + reaches(p)
print("durability against reach")
print(" survive turnover : " + str(survive) + " of " + str(len(places)))
print(" survive AND reach : " + str(survive_and_reach))
print(" survive and do NOT reach: " + str(survive - survive_and_reach))
if survive > survive_and_reach:
print(" a lesson can be permanent and still never arrive")
print("")
informed_reach = 0
for p in places:
if p[1] == 1:
informed_reach = informed_reach + 1
else:
informed_reach = informed_reach + 1
print("control - a reader who already knows the lesson exists")
print(" places they can use : " + str(informed_reach) + " of " + str(len(places)))
print(" which is why the document passes review")
print("")
print("The lesson was recorded and the recording is correct. Whether it is on the")
print("path the next person walks is a property of the place, and the place is")
print("chosen by whoever writes the postmortem rather than by whoever needs it.")stdout (executed)
textplaces a lesson can be filed : 7
place at the moment needs prior knowledge survives turnover reaches
a wiki page no yes yes no
the postmortem document no yes yes no
a team chat message no no no no
onboarding training no yes no no
a comment at the call site yes no yes YES
a test that fails yes no yes YES
a lint rule yes no yes YES
places that reach the person who needs it : 3 of 7
the ones that do not reach
a wiki page
the postmortem document
a team chat message
onboarding training
not present at the moment of need : 4
present but require knowing to look : 0
the ones that reach
a comment at the call site
a test that fails
a lint rule
all three are in the path of the work, not in a description of it
durability against reach
survive turnover : 5 of 7
survive AND reach : 3
survive and do NOT reach: 2
a lesson can be permanent and still never arrive
control - a reader who already knows the lesson exists
places they can use : 7 of 7
which is why the document passes review
The lesson was recorded and the recording is correct. Whether it is on the
path the next person walks is a property of the place, and the place is
chosen by whoever writes the postmortem rather than by whoever needs it.Trace event types
eml:run:starteml:assigneml:defeml:outputeml:calleml:returneml:run:done