Every feature has a marginal cost now, and it is not in the spec

A feature that calls a model has a per-use cost that scales with adoption. That makes success and cost the same curve, and it means the usual way of deciding what to build — impact against engineering effort — is missing a term that only shows up once the feature is popular.

Try for free Read the docs

What a provider dashboard leaves you with

01
Feature-level cost is not measurable, so the trade-off is made without it.
02
A successful launch and a cost incident look identical from the provider dashboard.
03
No way to tell whether a cheaper model would have been good enough for a given feature.

What Capsera does about it

Spend per feature: Give each feature's agent an identity and its cost separates out, so adoption and spend can be read against each other.
An envelope per feature: A budget scoped to the agent behind a feature, so a launch cannot consume the whole month.
Model choice as a decision, not a default: Cost-aware routing makes 'would a cheaper model do' a question you can answer per feature instead of guessing once.

The number this is judged on

Cost per active user, per feature

None of this is assumed. We scanned 133 public agent repositories and found a cost defect in most of the ones making live model calls.

Read the method and limitations

import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")

    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()

assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",

 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):

)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:

        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic

def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)

for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02

from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(

)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:

 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")

    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()

assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",

 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):

)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:

        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic

def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)

for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02

from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(

)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:

 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")

    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()

assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",

 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):

)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:

        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic

def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)

for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02

from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)
 
# checked before the call
capsera.budget(
    monthly=500,
    on_exceed="block",
)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(

)
 
with capsera.agent("summarizer"):
    client = Anthropic()
    resp = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
    )
 
# no proxy, no gateway
assert resp.usage.cost < 0.02
 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:

 
if capsera.over_budget():
    raise BudgetExceeded()
 
@capsera.track()
def extract(doc):
    return chain(doc)
 
# cheaper route, same output
capsera.route(prefer="cost")
 
spend = capsera.usage(
    group_by="agent",
    window="30d",
)
 
for a, cost in spend:
    print(a, f"${cost:.2f}")
 
# fails open, always
capsera.flush()
 
for task in queue:
    run(task)
 
log("run complete")
import capsera
from anthropic import Anthropic
 
capsera.init(
    agent="reasoning_agent",
    run_id=ctx.run_id,
)

Ship the feature knowing what it spends.

Stop runaway agents before they become runaway invoices.

Try for free