The agent sandbox meter has not converged
The agent's execution sandbox has become a billable unit at 9 of 353 corpus vendors, but nobody agrees what the unit is: 6 distinct shapes are live simultaneously and only per-vCPU-time plus per-memory-time has more than one adopter. The enabler is that agents now hold long-lived stateful compute, which neither a token meter nor a request meter prices. The divergence is structured, not random — infrastructure-shaped meters bill for capacity held while session-shaped meters bill for agent time — and the two are not inter-convertible without knowing a sandbox's core count and duration, which is exactly what a buyer does not know before deployment. The open question is which family wins: if the session shape spreads, the sandbox becomes its own unit; if vendors fall back to vCPU-time, it was never a new unit at all, only cloud compute at a multiplier, which is what Modal already says out loud at roughly 3x its own standard function rates.
Evidence over time
9 supporting · 3 counter — hover or tap a point for detail, click to jump to the row.
Evidence
| Company | Date | What happened |
|---|---|---|
| Perplexity | Jul 2026 | Added a fifth Agent API tool, `sandbox`, at $0.03 per container session — the docs are explicit that "a session covers up to 20 minutes of active use for billing purposes; this is the billing window, not a runtime cap." The changes record calls it Perplexity's first meter that counts neither tokens nor requests. SDK search queries issued from inside the sandbox bill separately at $0.005, halved to $0.0025 on 2026-07-29 while the $0.03 per-session fee was left untouched. The only flat-per-session sandbox price in the corpus. |
| Anthropic | Jun 2026 | Claude Managed Agents bills $0.08 per session-hour of runtime as a second meter on top of standard token rates, measured to the millisecond and accruing only while session status is "running" — and it explicitly REPLACED Code Execution container-hour billing, so Anthropic has already changed its own sandbox unit once. Restated on the API pricing page at the 2026-07-23 capture. The only per-session-hour price in the corpus. |
| Modal | Jul 2026 | Shipped a dedicated Sandbox + Notebooks rate card at $0.00003942/core/sec CPU and $0.00000667/GiB/sec memory (= $0.142/core-hr, $0.024/GiB-hr) — roughly 3x the standard function rates — while GPU on sandboxes still follows the standard per-second card. The same release itemised region selection at 1.5-1.75x and non-preemptible execution at 3x, so Modal frames the sandbox not as a new unit but as ordinary compute with a multiplier. |
| Together AI | Jul 2026 | Code Sandbox published at $0.0446/vCPU-hour plus $0.0149/GiB-hour, a two-part compute-plus-memory unit, confirmed unchanged week-over-week alongside dedicated inference and GPU-cluster rates. The cleanest example of the plurality shape stated in hours rather than seconds, which is itself a comparison tax: three of the four vendors using this shape denominate per second. |
| Novita AI | Jun 2026 | The earliest sandbox meter in the corpus (Agent Sandbox live on the pricing page's own tab by the 2025-08-04 Wayback snapshot) began publishing its underlying per-unit rate card on 2026-06-24: $0.0000098/vCPU-second, $0.0000032/GiB-second and $0.00009/GB-hour with the first 60 GB included, alongside a $100 / 90-day free-credit offer. Novita's own worked example prices a 5-minute coding-agent task on 1 vCPU + 512 MiB at roughly $0.0034. Unchanged at the 2026-07-21 and 2026-07-29 captures. |
| Upstash | Mar 2026 | Box prices agent sandboxes per ACTIVE CPU hour — $0.10 Small / $0.20 Medium / $0.40 Large — with idle boxes costing nothing and freezing automatically, plus storage at $0.10/GB/month. The vendor's own worked example: "using 100% of 2 cores for one hour costs $0.2, while using 10% of a single core for one hour costs $0.01." A flat Keep-Alive always-on mode was added in June 2026 at $8/$16/$32 per month, replacing both CPU and storage billing on that box — two different units for the same product. Free tier 10 concurrent boxes / 5 CPU hours per month; the page still carries a "pricing may change" Developer Preview banner. |
| LangChain / LangSmith | Jul 2026 | Sandbox rates were re-denominated out of dollars into proprietary LCU/LSU units at exactly the prior price (0.0384 LCU/vCPU-hr x $1.50 = $0.0576/vCPU-hr, the previously published rate), inside a wider collapse of a seven-meter rate card into two normalised units. The unit shape is unchanged; its comparability to other vendors is gone. Seats held at $0 Developer / $39 Plus. |
| OpenAI | Jul 2026 | The GPT-5.6 API refresh added Containers tool pricing: 1 GB for $0.03 or 64 GB for $1.92 per container — a flat price tiered by container SIZE, not time — with the pricing table noting the SKU moves to per-20-minute-session-per-container billing from March 31, 2026, a date already past at capture, so both shapes are documented on the page at once. The $0.03 figure is identical to Perplexity's per-session fee and the 20-minute window identical to Perplexity's billing window. |
| Composio | Jul 2026 | Two of the six metered dimensions replacing its single tool-call meter (effective 2026-08-15, existing customers grandfathered to 2026-12-31) are sandbox GB-hr and filesystem GB — storage-shaped units for the same capability Perplexity sells per session and Anthropic per session-hour. The only vendor in the corpus pricing a sandbox primarily on bytes held rather than on compute or time. |
Counterexamples
- E2B · Jul 2026 — The pure-play bounds the whole claim. E2B is a sandbox company, so its unit is a product decision rather than a packaging experiment — and it uses the plurality shape: $0.000014/s per vCPU (the default 2-vCPU sandbox is $0.000028/s) plus $0.0000045/GiB-second RAM and storage, on a $0 Hobby / $150-per-month Pro access fee that grants ceilings, not credits. Per-vCPU rates have not moved across the full tracked range. If the generalist platforms converge on this shape, the "agent sandbox meter" was never a new unit — it was E2B's unit, and cloud compute's before that.
- Fireworks · Jul 2026 — One of the most active packaging movers in the corpus declined the meter entirely. In the same fortnight it shipped Fire Pass (a zero-per-token non-production pass, upgraded on 2026-07-29 to grant Kimi K3 Fast at a 1M-token context) and a Serverless Training API metered across four new token dimensions ($0.66-$32.55 per 1M by stage and model) — but added no sandbox dimension. A vendor willing to add four meters in a week and not this one is evidence the unit is optional, not inevitable.
- Cognition (Devin) · Jul 2026 — Sells cloud agent sessions and publishes no per-sandbox rate at all. Devin Cloud sessions became paid-only at the 2026-07-21 plan-table split, but they are rationed by plan-level quota (Max advertises a "weekly allowance with no daily cap", up to 10 concurrent sessions) with Enterprise billed in Agent Compute Units "at the rate set in their order form". Prices held at $0/$20/$200 and $80 + $40 per full dev seat. The agent-session vendor most exposed to sandbox cost is the one that publishes no sandbox unit.
Trivia
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The unit shapes diverge but the price level does not, which is why the non-convergence is easy to miss. Price 20 minutes of a small sandbox three ways and the answers land within about 35% of each other on three incompatible meters: Perplexity charges a flat $0.03 per session with a 20-minute window (2026-07-21); Anthropic's $0.08 per session-hour (2026-06-15) works out to $0.027; E2B's default 2-vCPU/512-MiB sandbox at $0.000028/s compute plus $0.0000045/GiB-s memory comes to about $0.036. OpenAI's Containers price for a 1 GB container is also exactly $0.03. The convergence is illusory — Perplexity's price is invariant to cores and duration, Anthropic's scales with wall-clock, and E2B's scales with cores times seconds, so the ranking flips the moment the workload changes shape.
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Anthropic is the only vendor in the corpus that has already replaced its own sandbox unit: the Claude Managed Agents meter announced 2026-06-15 — $0.08 per session-hour, measured to the millisecond and accruing only while session status is "running" — explicitly superseded Code Execution container-hour billing. LangSmith did something subtler on 2026-07-21, re-denominating its sandbox rate out of dollars into its own currency at exactly the prior price (0.0384 LCU x $1.50 = $0.0576 per vCPU-hr), which removed the number from cross-vendor comparison without changing what it costs.
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The sandbox meter is older than the agent-pricing debate around it. The earliest instance in the corpus is Novita's Agent Sandbox, live on a per-vCPU-second and per-GiB-second rate card by 2025-08-04 — seven months before Upstash Box (2026-03-09) and eleven before Perplexity's per-session price — and pure per-second compute is still the plurality shape at 4 of the 9 vendors. Converted to a common denominator, four of them land in a narrow band (Novita $0.035/vCPU-hr, Together AI $0.0446, E2B $0.050, LangSmith $0.0576) while Modal deliberately sits 2.4-4x above at $0.142/core-hr, which it describes as roughly 3x its own standard function rate.