Plivo Voice API by Plivo

# Fix list: Plivo Voice API

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/plivo-voice, the October 2026 research run, assessed 1 October 2026. Grade C, 60.4 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Plivo Voice API: work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Security & auth, 45 out of 100, up to 9.6 more on the total

Why it scored 45: HTTP Basic auth with an Auth ID and Auth Token per account or subaccount. No per-key scopes found (20). Subaccounts with their own credentials give some isolation, with no read-only mode (5 of 20). Calls carry untrusted caller speech. Webhooks are signed, and we found no prompt-injection guidance (5 of 15). Call detail records and recordings by API, no customer-facing audit log found (10 of 15). SOC 2 audited annually, PCI DSS Level 1 and HIPAA per the security page. No security.txt, bug bounty or disclosure policy found (5 of 20).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 2. Payments & pricing, 40 out of 100, up to 7.5 more on the total

Why it scored 40: No x402, MPP or L402 (0). US per-minute, number, recording and transcription prices published without a login (20). $10 trial credit without a card, per the pricing page cited in the listing (20). A person signs up in a browser and verifies a phone number (0).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 3. Schema & documentation, 59 out of 100, up to 6.7 more on the total

Why it scored 59: No OpenAPI spec found (0). llms.txt at plivo.com/docs/llms.txt (10). Reference pages state what each endpoint and XML element does, with little on when not to use one (12 of 20). Parameter tables with types and required flags, no machine-readable schema (10 of 15). Examples in each SDK language, and hangup causes such as 5030, 5180 and 5190 are documented, though there's no full error catalogue in one place (12 of 15). Versioned v1 path and a public changelog (15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 4. Reliability, 68 out of 100, up to 6.4 more on the total

Why it scored 68: Statuspage at status.plivo.com with components and a readable history feed (20). One major incident in the last 90 days, call status webhooks not firing for a subset of calls for about 6.5 hours on 25 August while calls themselves connected. The other entries were India routes (failures for about 10 hours on 31 July and 1 August, and shorter ones on 20 July and 11 September), which we count as single-country and minor (10). Limits are published with numbers, 300 API requests per 5 seconds, 1 or 2 outbound calls a second and 2 to 50 concurrent calls by plan, 10 inbound a second (15). 429 is documented and the page says to retry after a short delay once calls end, with no Retry-After or backoff guidance (8 of 15). Plivo's Platform Service Levels document (2024-12-20) covers support response times but states no availability figure or credits (5 of 10). Voice API is generally available (10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 5. Agent ergonomics, 70 out of 100, up to 4.9 more on the total

Why it scored 70: List calls takes limit and offset, with no field selection (15 of 25). Call and recording lists filter by number, time and duration (20). HTTP errors plus documented hangup causes an agent can map to a fix (15 of 20). No idempotency key on call creation. Calls over the CPS limit are queued on the Voice API, and the only retry advice is to wait for active calls to end (5 of 20). Official SDKs in Node, Python and other languages, and a call needs from, to and answer_url (15).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 6. Transparency & trust, 70 out of 100, up to 2.6 more on the total

Made of editorial 50, provenance 90.

Why it scored 70: Closed service with clear terms at plivo.com/legal/tos (15). Privacy policy, encryption at rest and in transit, recordings kept 90 days free, and a sub-processor list. We didn't find a DPA or call-log retention periods (20 of 30). No deprecation policy or dated notices found (0). About 40 sub-processors listed with purpose and location (all USA), last updated 2025-08-13, with no change alerts (15 of 20).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- security.txt: not found (0 of 10)

## 7. Maintenance & community, 78 out of 100, up to 1.9 more on the total

Why it scored 78: plivo-python v4.63.0 on 2026-09-25, a fix to auto-pagination on Call and Recording lists (30). plivo-node v4.79.0 and plivo-python v4.62.0 on 2026-07-28, so three SDK releases in 90 days (20). Closed service with a public changelog and support. We didn't sample GitHub issue replies (8 of 15). Official SDKs current in several languages (15). CI and dependency state not checked, and plivo-node hasn't released since July (5 of 10).

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- Whether Plivo publishes a DPA or an availability commitment beyond the support-only service levels document
- Whether the trial credit is still $10, which we took from the listing's pricing source rather than rechecking
- Whether a Retry-After header comes back on 429

## Weaknesses

- 1 outbound call a second and 2 concurrent calls on the free tier, 5 on a new paid US account
- No OpenAPI spec, availability SLA or DPA found
- No MCP server that can place calls, the official one searches docs only
- Call status webhooks failed for a subset of calls for about 6.5 hours on 25 August
- No scoped keys, security.txt or bug bounty

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Point the answer URL at XML with a Stream element and bidirectional set to true for a live voice agent
- Check concurrency before dialling out in bulk. Above it calls are rejected with hangup cause 5030, above CPS they queue
- Don't rely on the status callback alone to learn a call ended. Poll the call if the webhook doesn't arrive
- Validate webhook signatures before acting on call events

## What the review panel asked for

- List the streaming charge
- publish an availability SLA
- add Retry-After to 429

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.