fone.me vs Retell AI API + MCP

fone.me 23

Closed service. The newest dated change to the agent surface found is the MCP repository github.com/spearisa/fone-me-mcp, created 5 October 2026 with server.json version 1.0.0, 31 days ago (20). The comparison page marked 'Checked October 28, 2026' and the profile lastmods in the sitemap are content, not releases. No changelog, release notes or three dated changes in 90 days (0 of 20). The support page and FAQ draw by script and no support email, forum or community channel was found; responsiveness unchecked (3 of 15). server.json names the server me.fone.www/agents, a namespace that needs proof of the domain, but the official MCP registry could not be read, so presence is scored absent (0 of 15). No package, public code or CI (0 of 10). 20+0+3+0+0 = 23.

Retell AI API + MCP 85

TypeScript and Python SDKs v6.2.16 on 31 October 2026 (30). 19 SDK releases from 5 October to 31 October alone, plus 6.0.0 and 6.0.1 on 14 September (20). Public changelog and deprecation feed, support we didn't test (12 of 15 for a closed service). Node.js and Python SDKs current (15). SDK CI restored on 10 September (8 of 10).

fone.me 31

MCP reading, since the MCP server is what an outside agent calls. No tool arguments or input schemas are published in llms.txt, the guide pages or the GitHub README, and robots.txt disallows /mcp, so no session was opened and tools/list was not read. Per-link A2A agent cards are machine-readable JSON (protocol 0.3.0, JSONRPC, input and output modes, skills with examples) and server.json names the remote, but neither types the MCP tools (8 of 25). llms.txt is a real document for agents covering the MCP server, A2A, the search API and the widget (10). Each tool has a one-line purpose in llms.txt and the README, and the how-it-works page states what the agent will and won't do; nothing says when not to use a tool (6 of 20). No typed inputs, enums, constraints or required fields published (0 of 15). Example prompts in the README, per-skill examples in agent cards and widget code for eight site builders; no error response is documented (4 of 15). server.json and the agent cards carry version 1.0.0 and the cards a protocol version; no changelog (3 of 15). 8+10+6+0+4+3 = 31.

Retell AI API + MCP 92

OpenAPI at docs.retellai.com/openapi-final.yaml (25). llms.txt with descriptive one-line summaries for each page (10). Pages say when to use a single-prompt agent and when a conversation flow (16 of 20). Typed request bodies with enums and required fields (13 of 15). Examples throughout and typed errors in the SDKs (13 of 15). A dated changelog, SDK releases and a deprecation-notice page with an RSS feed (15).

fone.me 23

Closed service. Terms of service exist at /terms but draw by script, so their content, governing law and the company they name are unchecked; no company, address or country of incorporation appears on any page read, llms.txt says San Francisco, and the MCP repository has no licence (5 of 30). Data handling was read only from guide pages, which say only the owner sees their calls and messages, calls are transcribed and callers told so, and private categories are withheld. The privacy policy and data-deletion page draw by script, so no retention period, recording statement, DPA or AI-training statement was read (8 of 30). No deprecation policy or dated notices (0). No subprocessors, telephony, model or hosting providers or data locations are named on any page read; the demo agent card's icon is served from Cloudinary (0 of 20). 5+8+0+0 = 13.

Retell AI API + MCP 77

Closed platform with clear terms and Apache-2.0 SDKs (18 of 30). Call data is kept indefinitely unless a per-agent retention period from 1 to 730 days is set, and the compliance page covers BAA, DPA and erasure. The statements agree, though keeping data forever is the default (22 of 30). Dated deprecation notices with an RSS feed, such as the legacy MCP server shutdown on 20 July 2026 (20). The 27 May 2026 changelog announced new subprocessors (Soniox, Ironclad). We didn't check data locations (15 of 20).

fone.me 30

No credential exists for callers. llms.txt gives auth 'none', the README says the server is 'public, like the links themselves', and the two agent cards read declare no security scheme. There is nothing to leak or rotate, but fone.me and an owner can tell callers apart only by the name they give ('Maria via ChatGPT' in the README) and by traffic, and no caller identity or verification is documented (10 of 30). Three of four MCP tools are lookups; message_agent and A2A message/send reach any owner's agent. On the owner's side the vendor says the agent asks before agreeing to anything or spending money, the owner approves what it will say before a call, outbound calls run only 8 am to 9 pm local, pause when reported and stop permanently on request, and the owner can take over any chat. No read-only mode and no confirmation on the caller's side (8 of 20). message_agent returns text generated from what the owner taught the agent, and every agent on the platform reads messages from anyone; the only guidance is the how-it-works statement that the agent keeps relationship status, health, money and address private, with no documented prompt-injection or spam handling for the open channel, and the call-screening page says it does not promise to block calls (4 of 15). Owners see every call and chat with a transcript in one inbox; nothing is logged for the calling agent (8 of 15). /.well-known/security.txt answers with the app shell, and no disclosure policy, bug bounty or certification appears on any page read (0 of 20). 10+8+4+8+0 = 30.

Retell AI API + MCP 76

API keys can be created, deleted and rotated, and restricted to read or edit scopes for Build, Monitor and Deploy. Public keys for web calls can be limited to domains with reCAPTCHA (30). Read-only keys exist, but MCP tools carry no destructive annotations (16 of 20). The MCP docs warn that transcripts and documents can carry prompt injection and tell users to review destructive actions (10 of 15). Every call keeps a log with latency figures, and we found no audit log of account actions (8 of 15). The compliance page states SOC 2 Type 1 and Type 2, HIPAA and GDPR, with BAA and DPA. No security.txt or bug bounty found (12 of 20).

fone.me 15

Hosted reading, for the MCP server and A2A endpoints and the service behind them. No status page is linked from llms.txt, the home page or any guide page read, and https://www.fone.me/status failed to load (0). No readable incident history, so the floor (5). No request rate limit for the MCP server, the search API or A2A is published; the only limits are on the agent's own outbound calls (8 am to 9 pm in the callee's time zone, 'limited per day' with no number), which are not request limits (0 of 15). No 429, overload or retry guidance and no idempotency key for message_agent or message/send (0 of 15). No SLA (0). Nothing on the MCP server, the agent cards or llms.txt is marked beta or preview, and the MCP repository's server.json is version 1.0.0 (10). 0+5+0+0+0+10 = 15.

Retell AI API + MCP 60

Statuspage at status.retellai.com with an incident feed back to 10 December 2025 (20). Four incidents since 3 August 2026, read from history.atom on 1 November. Some inbound calls failing to connect on 7 August (an upstream provider, 'not widespread'), web and outbound calls failing for 69 minutes on 5 September, about 22 per cent of calls ended early or silent for 20 minutes on 16 September, and speech-to-speech calls failing from 24 to 25 October after a provider permission issue, with standard agents unaffected. We count 5 September as one major and the others as partial (10). 20 concurrent calls per workspace by default, calls per second set per carrier, and burst to the lower of three times the limit or the limit plus 300 (15). Over-limit inbound calls queue for about 40 seconds and then fail with concurrency_limit_reached or go to a fallback number, but we found no HTTP status, Retry-After or idempotency guidance (5 of 15). No SLA found for pay as you go (0). Generally available (10).

fone.me 29

MCP reading. Four tools named in llms.txt, a small set, but their definitions were not read, so short of full marks (18 of 25). find_agents searches by what someone does and the search API takes a query; no limit, paging or output-size controls are documented (3 of 20). No error codes or messages documented for the MCP server, the search API or A2A (0 of 20). No readOnlyHint or destructiveHint seen and no idempotency key; the three lookups are read-only by name and description, while message_agent writes to a real person's inbox and continues the conversation across calls (2 of 20). No credentials, no configuration beyond the URL, and few stated inputs; no SDK in any language (6 of 15). 18+3+0+2+6 = 29.

Retell AI API + MCP 60

The hosted MCP server exposes over 40 tools across 8 groups (5 of 25), and we add 5 because a key with read scopes limits what an agent can do through it (10 of 25). Call lists filter and page (16 of 20). Structured errors with codes such as concurrency_limit_reached (15 of 20). No idempotency keys and no tool annotations. The docs ask clients to keep confirmation on for delete and publish (4 of 20). Typed SDKs for Node.js and Python with few required fields to place a call (15).