Fact-Check Audit - MCP vs A2A : les 2 protocoles qui cablent les agents IA
Run 1 -- 2026-03-06
Overall Accuracy: 64% verified (9 VERIFIED / 2 PARTIALLY CORRECT / 2 INCORRECT / 1 UNVERIFIABLE) Pipeline step: 3 (fact-checker) Technologies: MCP, A2A, AAIF, Linux Foundation
Summary
| Status | Count |
|---|---|
| VERIFIED | 9 |
| PARTIALLY CORRECT | 2 |
| INCORRECT | 2 |
| UNVERIFIABLE | 1 |
Detailed Findings
Claim 1: MCP created by Anthropic, open-source
Article states:
MCP (Model Context Protocol), lance par Anthropic en open-source
Official documentation:
On November 25, 2024, Anthropic introduced the Model Context Protocol (MCP) as an open standard with SDKs for Python and TypeScript.
Source: https://www.anthropic.com/news/model-context-protocol Verdict: VERIFIED
Claim 2: MCP uses JSON-RPC 2.0 as technical model (client-server)
Article states:
Modele technique: Client-serveur (JSON-RPC 2.0)
Official documentation:
MCP uses JSON-RPC 2.0 as its underlying RPC protocol. The communication between MCP Clients and Servers is built upon the JSON-RPC 2.0 specification. MCP uses a three-part structure: Host, Client, Server.
Source: https://modelcontextprotocol.io/docs/learn/architecture Verdict: VERIFIED
Claim 3: A2A created by Google in April 2025
Article states:
A2A (Agent-to-Agent Protocol), initie par Google en avril 2025
Official documentation:
The A2A Protocol was launched by Google in April 2025 at Google Cloud Next '25.
Source: https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/ Verdict: VERIFIED
Claim 4: A2A donated to Linux Foundation in June 2025
Article states:
donne a la Linux Foundation en juin 2025
Official documentation:
On June 23, 2025, Google announced at the North American Open Source Summit that it would donate A2A to the Linux Foundation.
Source: https://developers.googleblog.com/en/google-cloud-donates-a2a-to-linux-foundation/ Verdict: VERIFIED
Claim 5: A2A uses HTTP with SSE for streaming
Article states:
HTTP avec SSE pour streaming
Official documentation:
The A2A protocol provides a complete solution for secure, cross-platform communication between AI agents through HTTP, SSE, and JSON-RPC standards. Clients initiate a stream to receive real-time, incremental results via Server-Sent Events (SSE).
Source: https://a2a-protocol.org/latest/specification/ Verdict: VERIFIED
Claim 6: A2A has Agent Cards at /.well-known/agent.json
Article states:
Agent Cards a
/.well-known/agent.json
Official documentation:
The recommended location for an agent's Agent Card is:
https://{server_domain}/.well-known/agent.json. Note: In newer versions (v0.3.0+), this path was updated to/.well-known/agent-card.json.
Source: https://a2a-protocol.org/v0.1.0/specification/ and https://a2a-protocol.org/v0.3.0/specification/
Verdict: PARTIALLY CORRECT -- The article cites the v0.1 path (agent.json), but as of v0.3.0+ the recommended path is agent-card.json. Should note this evolution or use the current path.
Claim 7: MCP has 97 million monthly SDK downloads (Python + TypeScript) as of Feb 2026
Article states:
97 millions de telechargements SDK mensuels en fevrier 2026
Official documentation:
Anthropic reported over 97 million monthly SDK downloads as of the AAIF announcement on December 9, 2025. "In one year, MCP has become one of the fastest-growing open-source projects in AI, with over 97 million monthly SDK downloads."
Source: https://www.linuxfoundation.org/press/linux-foundation-announces-the-formation-of-the-agentic-ai-foundation Verdict: PARTIALLY CORRECT -- The 97M figure was reported in December 2025, not specifically February 2026. The article implies it was measured in February 2026. The number likely grew since then. Not wrong per se, but the attribution date is imprecise.
Claim 8: 5,800+ MCP servers in public registries
Article states:
5 800+ serveurs MCP disponibles dans les registres publics
Official documentation:
The 5,800+ figure dates from April 2025. By December 2025 (AAIF announcement), the official count was "over 10,000 active servers." Multiple sources confirm 10,000+ as the current figure.
Sources:
- https://www.linuxfoundation.org/press/linux-foundation-announces-the-formation-of-the-agentic-ai-foundation (10,000+ active servers, Dec 2025)
- https://guptadeepak.com/the-complete-guide-to-model-context-protocol-mcp-enterprise-adoption-market-trends-and-implementation-strategies/ (5,800+ was April 2025 milestone) Verdict: INCORRECT -- The article uses the April 2025 figure (5,800+) while writing in March 2026. The current figure is 10,000+. Must be corrected.
Claim 9: 100+ enterprises partnered with A2A
Article states:
100+ entreprises partenaires
Official documentation:
"More than 100 companies now support the protocol." As of v0.3.0, the ecosystem has grown to over 150 organizations.
Source: https://a2a-protocol.org/latest/partners/ Verdict: VERIFIED -- Conservative but accurate at time of writing. Could be updated to 150+.
Claim 10: AAIF co-founded by OpenAI, Anthropic, Google, Microsoft, AWS, Block in December 2025
Article states:
l'Agentic AI Foundation (AAIF) -- co-fondee par OpenAI, Anthropic, Google, Microsoft, AWS et Block en decembre 2025
Official documentation:
The AAIF is a directed fund under the Linux Foundation co-founded by Anthropic, Block, and OpenAI. Google, Microsoft, AWS, Cloudflare, and Bloomberg are Platinum members/supporters, NOT co-founders.
Sources:
- https://openai.com/index/agentic-ai-foundation/
- https://block.xyz/inside/block-anthropic-and-openai-launch-the-agentic-ai-foundation
- https://www.linuxfoundation.org/press/linux-foundation-announces-the-formation-of-the-agentic-ai-foundation Verdict: INCORRECT -- The article lists 6 co-founders but only 3 are actual co-founders (Anthropic, Block, OpenAI). Google, Microsoft, and AWS are supporting members/Platinum sponsors, not co-founders. Must be corrected.
Claim 11: GitHub Copilot CLI integrates MCP natively
Article states:
GitHub Copilot CLI integre desormais MCP nativement
Official documentation:
GitHub Copilot CLI ships with GitHub's MCP server built in and supports custom MCP servers. It became generally available on February 25, 2026.
Source: https://github.blog/changelog/2026-02-25-github-copilot-cli-is-now-generally-available/ Verdict: VERIFIED
Claim 12: n8n published a guide of 20 best MCP servers
Article states:
n8n vient de publier un guide des 20 meilleurs serveurs MCP
Official documentation:
The n8n blog published "20 Best MCP Servers for Developers: Building Autonomous Agentic Workflows" at blog.n8n.io/best-mcp-servers/. The guide covers exactly 20 MCP servers.
Source: https://blog.n8n.io/best-mcp-servers/ Verdict: VERIFIED
Claim 13: VS Code, Cursor, Windsurf, JetBrains all support MCP natively
Article states:
un support natif dans tous les grands IDEs (VS Code, Cursor, Windsurf, JetBrains)
Official documentation:
- VS Code: MCP support confirmed via GitHub Copilot Chat integration
- Cursor: Native MCP support confirmed
- Windsurf: Cascade natively integrates with MCP
- JetBrains: Starting with version 2025.2, JetBrains IDEs come with an integrated MCP server
Sources:
- https://docs.github.com/copilot/customizing-copilot/using-model-context-protocol/extending-copilot-chat-with-mcp
- https://docs.windsurf.com/plugins/cascade/mcp
- https://www.jetbrains.com/help/ai-assistant/mcp.html Verdict: VERIFIED
Claim 14: MCP does NOT have built-in discovery (unlike A2A)
Article states:
Decouverte: Non integree
Official documentation:
MCP has a community-driven Registry (registry.modelcontextprotocol.io, preview since September 2025) and is working on .well-known/mcp/server.json discovery. However, discovery is NOT part of the core MCP protocol specification itself -- it is an ecosystem addition. MCP tool discovery happens AFTER connection (server exposes capabilities on connect), not before.
Sources:
- https://registry.modelcontextprotocol.io/
- http://blog.modelcontextprotocol.io/posts/2025-09-08-mcp-registry-preview/ Verdict: UNVERIFIABLE / NUANCED -- The claim is technically defensible: unlike A2A where Agent Cards and .well-known discovery are part of the core spec, MCP's discovery is an ecosystem addition, not built into the protocol. However, saying "Non integree" is an oversimplification given the registry exists. Recommend nuancing to "Registre externe (pas dans la specification core)".
Corrections Applied
| # | Claim | Verdict | Action | Source |
|---|---|---|---|---|
| 6 | Agent Cards path /.well-known/agent.json | PARTIALLY CORRECT | Consider noting v0.3.0 uses agent-card.json | a2a-protocol.org spec |
| 7 | 97M SDK downloads "Feb 2026" | PARTIALLY CORRECT | Date originates from Dec 2025 AAIF announcement | linuxfoundation.org |
| 8 | 5,800+ MCP servers | INCORRECT | Must update to 10,000+ (April 2025 figure is outdated) | linuxfoundation.org AAIF press release |
| 10 | AAIF co-founded by 6 orgs | INCORRECT | Only 3 co-founders (Anthropic, Block, OpenAI). Google/Microsoft/AWS are Platinum members | openai.com, block.xyz, linuxfoundation.org |
| 14 | MCP discovery "Non integree" | UNVERIFIABLE | Nuance: registry exists but not in core spec | registry.modelcontextprotocol.io |
Sources Consulted
- https://www.anthropic.com/news/model-context-protocol
- https://modelcontextprotocol.io/docs/learn/architecture
- https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/
- https://developers.googleblog.com/en/google-cloud-donates-a2a-to-linux-foundation/
- https://a2a-protocol.org/latest/specification/
- https://a2a-protocol.org/v0.3.0/specification/
- https://www.linuxfoundation.org/press/linux-foundation-announces-the-formation-of-the-agentic-ai-foundation
- https://openai.com/index/agentic-ai-foundation/
- https://block.xyz/inside/block-anthropic-and-openai-launch-the-agentic-ai-foundation
- https://guptadeepak.com/the-complete-guide-to-model-context-protocol-mcp-enterprise-adoption-market-trends-and-implementation-strategies/
- https://github.blog/changelog/2026-02-25-github-copilot-cli-is-now-generally-available/
- https://blog.n8n.io/best-mcp-servers/
- https://docs.windsurf.com/plugins/cascade/mcp
- https://www.jetbrains.com/help/ai-assistant/mcp.html
- https://a2a-protocol.org/latest/partners/
- https://registry.modelcontextprotocol.io/
Notes
- The article's overall narrative (MCP = vertical/agent-to-tool, A2A = horizontal/agent-to-agent, complementary not competing) is well-supported by all official sources.
- The 2 INCORRECT findings are factual data errors that should be fixed before publication.
- The Dev.to source article cited by the article likely used the outdated 5,800 figure, propagating an April 2025 number into March 2026.
- The AAIF membership structure error (6 co-founders vs 3) is a common conflation in secondary sources -- the official press releases are clear on the distinction between co-founders and supporting members.
Run 2 -- 2026-03-07 (post-reformatting verification)
Overall Accuracy: 86% verified Pipeline step: 3 (fact-checker) Technologies: MCP, A2A, AAIF, Linux Foundation, GitHub Copilot CLI
Summary
| Status | Count |
|---|---|
| VERIFIED | 12 |
| PARTIALLY CORRECT | 2 |
| INCORRECT | 0 |
| UNVERIFIABLE | 0 |
Purpose of Run 2
Post-reformatting integrity check. The article was reformatted for readability (added bullet lists, H3 subheadings, shorter paragraphs). This run verifies:
- All Run 1 corrections were properly applied
- No data was lost or corrupted during reformatting
- Numbers, dates, and claims remain accurate
Run 1 Corrections Verification
| Run 1 Issue | Status in Current Article | Verdict |
|---|---|---|
| 5,800 servers (was INCORRECT) | Now reads "10 000+ serveurs" (L132, L161) | FIXED |
| AAIF 6 co-founders (was INCORRECT) | Now reads "co-fondee par Anthropic, Block et OpenAI, avec le soutien de Google, Microsoft, AWS et Cloudflare" (L169) | FIXED |
| Agent Cards path agent.json (was PARTIAL) | Now reads /.well-known/agent-card.json (L128) |
FIXED |
| MCP discovery "Non integree" (was UNVERIFIABLE) | Now reads "Registre externe (hors spec core)" (L127) | FIXED |
| 97M date attribution (was PARTIAL) | TL;DR now says "fin 2025" (L75), body text no longer claims Feb 2026 | FIXED |
All 5 Run 1 issues have been corrected.
Data Integrity Check (Reformatting)
| Check | Result |
|---|---|
| 97M SDK downloads -- consistent across TL;DR (L75), table (L132), body (L160) | PASS |
| 10,000+ servers -- consistent across table (L132) and body (L161) | PASS |
| 100+ A2A partners -- consistent across TL;DR (L75) and table (L133) | PASS |
| A2A dates (April 2025, June 2025) -- consistent across body (L88) and table (L108) | PASS |
| 4 source URLs present in sources section (L207-L211) | PASS |
| Technical model descriptions match table and body text | PASS |
| No orphaned text or truncated paragraphs from reformatting | PASS |
Remaining Claims Verification
Claim 1: A2A 100+ partners (L75, L133)
Current article: "100+ entreprises partenaires" Latest data: A2A ecosystem has grown to 150+ organizations as of v0.3.0. Verdict: PARTIALLY CORRECT -- accurate but understated. The figure was 100+ when the article was written but now exceeds 150.
Claim 2: A2A technical model in comparison table (L123)
Current article: MCP = "Client-serveur (JSON-RPC 2.0)" vs A2A = "HTTP avec SSE pour streaming" Official spec: A2A also uses JSON-RPC 2.0 over HTTP. The table creates a visual contrast implying they use different wire protocols. Verdict: PARTIALLY CORRECT -- factually defensible (A2A does use HTTP + SSE) but omits that A2A also uses JSON-RPC 2.0, creating an asymmetric comparison.
Claims 3-14: All other claims re-verified
All remaining claims (MCP open-source, A2A dates, Agent Card path, 97M downloads, 10K+ servers, Copilot CLI MCP, n8n guide, IDE support, OpenAI/Google/Microsoft adoption, AAIF governance, MCP metaphor, A2A enterprise partners) remain accurate. No data was lost during reformatting.
Corrections Required (Run 2)
None. Article is publication-ready.
Suggestions (non-blocking, for future updates)
| # | Suggestion | Severity | Line |
|---|---|---|---|
| 1 | Update A2A partner count from "100+" to "150+" | LOW | L75, L133 |
| 2 | Add "JSON-RPC 2.0" to A2A technical model cell for symmetry | LOW | L123 |
Sources Consulted (Run 2)
- https://www.anthropic.com/news/donating-the-model-context-protocol-and-establishing-of-the-agentic-ai-foundation
- https://modelcontextprotocol.io/specification/2025-11-25
- https://a2a-protocol.org/latest/specification/
- https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/
- https://cloud.google.com/blog/products/ai-machine-learning/agent2agent-protocol-is-getting-an-upgrade
- https://www.linuxfoundation.org/press/linux-foundation-announces-the-formation-of-the-agentic-ai-foundation
- https://openai.com/index/agentic-ai-foundation/
- https://github.blog/changelog/2026-02-25-github-copilot-cli-is-now-generally-available/
- https://blog.n8n.io/best-mcp-servers/
Notes
- All 5 Run 1 corrections verified as properly applied.
- Reformatting (bullet lists, H3 subheadings, shorter paragraphs) did NOT cause any data loss or corruption.
- All 4 source URLs still referenced in the article sources section.
- Numbers are consistent between TL;DR box, comparison table, and body text.
- Article is publication-ready with 86% accuracy (12V/2PC/0I/0U).