Context economics — the 99.2 %

Rule for this document: no figure is written by hand. Each one carries the command or the archivo:línea that produces it, and any figure without a declared denominator is not published.

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1 · The thesis in one sentence

The cost of an agent is not in what the model writes; it is in what the call drags along. Measured over
28 971 real calls across 5 days: output is 0.89 % of consumption. 99.11 % is input
(REPORTE_TOKENS.md:130).

Hence the uncomfortable corollary: optimising the model, the prompt or the temperature moves less than 1 % of
the bill. The remaining 99 % is decided by how many times the history is resent.

2 · The business number: cost per verified task

Not cost per call — cost per task, which is the unit in which it is billed and in which the decision is made.

metric (median per task)	value	n
total consumption of the task (input + output)	18 024 682.50 tok	10
of that, model output	141 574.50 tok	10
model calls that had to be chained	217.50	10
tokens resent per call (carry-over)	80 032.00	10

locus: REPORTE_TOKENS.md:185-188 @ blob 1c09a667 (213 l) — correct for the generation that §2 freezes; in the live generation the table lives at :188-197 @ blob bc67c4c5 (see §8.1).

A task costs 18.02 M tokens. Of those, 141.6 k —0.79 %— is what the model produced. The rest is the same
story told again two hundred and seventeen times.

Carry-over = 1 − 141 574.50 / 18 024 682.50 = 99.215 %.

It is not 95 %. It is 99.2 %. The difference matters: 95 % still allows the fantasy that the remaining 5 %
—«the real work»— is where the lever is. 99.2 % says there is no such 5 %.

3 · How it is reproduced (this is the part that gets billed)

The report is not an opinion with tables. It is a deterministic instrument over evidence from the machine's own
disk:

git cat-file blob bb7190b0 > /tmp/ttr.json           # el crudo de atribución, congelado por blob
.venv/bin/python tools/reporte_tokens.py --ttr /tmp/ttr.json --md-out /tmp/panel.md   # RC 150 = nominal

The verification run of 30-Oct-2026 reproduces 18 024 682.50 and 141 574.50 exactly, from blob
bb7190b0 and not from a lost temporary file. A third-party reader can do the same without asking us for
anything.

Why this is the commercial part and not the technical one: any vendor can say «we optimise your context».
What almost nobody can do is hand over the command with which the client checks the figure on their own
machine.

4 · The percentage trap: three denominators, three truths

Here is the finding that turns the article into something that does not exist in the agents literature: the
same saving measures three different figures depending on what it is divided against, and almost all published
material does not declare the denominator.

Measured case: cutting the profile's tool-schema block from 73 to 22 tools.

what it is divided against	figure	honest reading
the schema block of the profile that features it	57.9 %	«I cut the block by 58 %»
the input of that same profile	15.4 %	«I saved 15 % of the input»
the input of the whole corpus	8.73 %	«I saved 8.7 % of the spend»

All three are true. Only the third is «of the total», and it is the smallest. A vendor that publishes the first
as if it were the third is selling a number with a swapped subject — and that error is indistinguishable from a
lie in the contract, even when there is no intent.

The real weighted tax of the schema block is 730 356 952 / 2 472 640 471 = 29.54 % of the input
(REPORTE_TOKENS.md:142-160, sum over calls). Almost a third of the money goes into declaring tools.

5 · And pruning is not linear: the tax depends on the set, not on the count

The market intuition —«fewer tools, less cost»— is false, and the same panel refutes it:

tools exposed	tool_tokens per call	n
98	26 109.00	343
97	25 818.00	933
94	32 768.00	1
22	9 464.00	416
21	9 173.88	205

locus: REPORTE_TOKENS.md:147-160.

Fewer tools (94) cost 26.9 % more than more tools (97). And one tool fewer than 22 (that is, 21) costs
3.07 % less. The tax is set by the content of the block —which schemas, with which description and which
JSON schema—, not by its length in units.

Consequence for whoever is going to buy this: the right question is not «how far can we prune?» but
«which set, measured, for which task?». A contract that promises a percentage per cardinality threshold is
promising something the corpus does not support.

6 · What this article does NOT claim (and why saying it makes it sellable)

1. It does not claim cost per row. The 99.2 % is the median of a panel of 200 evaluated commits, with 10 attributed tasks. Attribution by link exists but is residual: por_enlace = 1, por_ventana = 199 (REPORTE_TOKENS.md:69). We cannot tell a client «your task costs X». We can tell them «the median task of this panel costs 18.02 M». It is a fleet dashboard, not a per-service receipt, and the receipt is the missing product.
2. It does not claim monetary savings. The runtime's cost field travels with isByok: true: a 0.0 there means «not billed to this account», not «free». Without rates there are no euros (REPORTE_TOKENS.md §8).
3. It does not claim routing. The comparison of models by cost is NO_MEDIDO for the same reason.

Publishing the limits does not weaken the article: it is the only way the three figures that are claimed can
be credible.

7 · Closing

The sector measures tokens the way one measures petrol: litres consumed. The difference between that and
economics is knowing how many of those litres moved the car and how many burned at the traffic light. In an
agent, the traffic light is the resent context, and in this measurement it is 99.2 of every 100 litres.

Whoever does not measure the carry-over is not optimising an agent: they are choosing a smaller engine for a car
that does not move.

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Full reproducible evidence: REPORTE_TOKENS.md · Instrument: tools/reporte_tokens.py (RC 150
nominal) · Frozen raw data: crudos/reporte_ttr_20261030.json @ bb7190b0.

8 · The figure has a date (and the ratio does not)

This article was written on one generation of the raw data, and it has to be said with a number because the
defect is the house speciality: the producer scans the host's session-state, which grows while it is being
written, so two runs of the same command on the same day do not give the same medians.

generation	raw blob	T_total median	T_completion median	calls	carry-over
§2 of this article	bb7190b0	18 024 682.50	141 574.50	217.50	99.215 %
live, in the repo	03e9072b	23 105 392.50	167 397.00	276.50	99.276 %
jump between the two	—	+28.19 %	+18.24 %	+27.13 %	+0.061 pp

That jump row is the article's thesis measured against itself. The absolute moves 28.19 % depending on
when the command is run; the ratio moves 0.061 percentage points. This is exactly why the number being sold
is a proportion and not a total: a proportion survives regeneration, a total does not.
Both generations give 99.2 % and 99.3 % — and in no case the 95 % that was circulating. One of the
four columns of §2, tokens por llamada = 80 032.00, is identical in both generations: the median of a ratio
stays put even when both its operands move.

Two consequences that are not hidden:

1. REPORTE_TOKENS.md:185-188 was overtaken by its own sidecar, and it has already been corrected there. The sidecar of the raw data (crudos/reporte_ttr_20261030.meta.json) declared, in the same tree, that «la primera generación publicó 18024682.5 / 141574.5 y esta publica 23105392.5 / 167397.0» and that «la cifra que vale es la del crudo con su blob». The report's §7 table published the first one: it was measured and corrected in REPORTE_TOKENS.md (commit 45917cec), where today it lives at :188-197 @ blob bc67c4c5 and publishes 23 105 392.50 / 167 397.00. The locus of §2 was not miswritten: it was correct for the blob it cites —1c09a667, 213 lines— and the neighbouring commit 6d74da06 displaced it, moving the table to 189-192 before the correction left it at 190-193. This section does not rewrite §2: §2 is left as it was written, with its frozen generation and its blob, so that the difference between the two is auditable instead of invisible. It is an addendum, not a replacement — now with the dated closing, not with the open debt.
2. Whoever runs the command today will get a third figure. The figure is not the product; the command is. That is why §3 hands over the command and the blob, not the table.

HUELLA-ARTICULO-ECONOMIA-CONTEXTO-VIGENCIA-20261030
HUELLA-ARTICULO-COLATERAL-M7-CERRADO-20261030``