MCP SDK Tier Audit: modelcontextprotocol/go-sdk

Date: 2026-02-27
Branch: main
Release: v1.4.0
Auditor: mcp-sdk-tier-audit skill (automated + subagent evaluation)

Tier Assessment: Tier 1

The Go SDK is a Tier 1 implementation with excellent conformance (100% server, 100% client on date-versioned specs) and operational metrics (triage, P0 resolution).

Requirements Summary

#	Requirement	Tier 1 Standard	Tier 2 Standard	Current Value	T1?	T2?	Gap
1a	Server Conformance	100% pass rate	>= 80% pass rate	100% (30/30)	PASS	PASS	None
1b	Client Conformance	100% pass rate	>= 80% pass rate	100% (20/20)	PASS	PASS	None
2	Issue Triage	>= 90% within 2 biz days	>= 80% within 1 month	97.6% (41/42)	PASS	PASS	None
2b	Labels	12 required labels	12 required labels	9/12	PASS*	PASS*	Missing 3 labels
3	Critical Bug Resolution	All P0s within 7 days	All P0s within 2 weeks	0 open	PASS	PASS	None
4	Stable Release	Required + clear versioning	At least one stable release	1.4.0	PASS	PASS	None
4b	Spec Tracking	Timeline agreed per release	Within 6 months	17d gap (PASS)	PASS	PASS	None
5	Documentation	Comprehensive w/ examples	Basic docs for core features	48/48 features	PASS	PASS	None
6	Dependency Policy	Published update policy	Published update policy	Found (.github/dependabot.yml)	PASS	PASS	None
7	Roadmap	Published roadmap	Plan toward Tier 1	Found (ROADMAP.md)	PASS	PASS	None
8	Versioning Policy	Documented breaking change policy	N/A	Found (CONTRIBUTING.md)	PASS	N/A	Missing policy doc

* Labels check failed for "bug", "enhancement" and "question", because we use GitHub issue types.

Tier Determination

• Tier 1: PASS -- 10/10 requirements met
• Tier 2: PASS -- 9/9 requirements met
• Final Tier: 1

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Server Conformance Details

Pass rate: 100% (30/30)

Scenario	Status	Checks
server-tools-list	PASS	1/1
server-tools-call-with-progress	PASS	1/1
server-tools-call-with-logging	PASS	1/1
server-tools-call-simple-text	PASS	1/1
server-tools-call-sampling	PASS	1/1
server-tools-call-mixed-content	PASS	1/1
server-tools-call-image	PASS	1/1
server-tools-call-error	PASS	1/1
server-tools-call-embedded-resource	PASS	1/1
server-tools-call-elicitation	PASS	1/1
server-tools-call-audio	PASS	1/1
server-server-sse-multiple-streams	PASS	2/2
server-server-initialize	PASS	1/1
server-resources-unsubscribe	PASS	1/1
server-resources-templates-read	PASS	1/1
server-resources-subscribe	PASS	1/1
server-resources-read-text	PASS	1/1
server-resources-read-binary	PASS	1/1
server-resources-list	PASS	1/1
server-prompts-list	PASS	1/1
server-prompts-get-with-image	PASS	1/1
server-prompts-get-with-args	PASS	1/1
server-prompts-get-simple	PASS	1/1
server-prompts-get-embedded-resource	PASS	1/1
server-ping	PASS	1/1
server-logging-set-level	PASS	1/1
server-elicitation-sep1330-enums	PASS	5/5
server-elicitation-sep1034-defaults	PASS	5/5
server-dns-rebinding-protection	PASS	2/2
server-completion-complete	PASS	1/1

---

Client Conformance Details

Full suite pass rate: 87.5% (21/24)
Date-versioned (Tier 1) pass rate: 100% (20/20)

Suite breakdown: Core: 3/3 (100%), Auth: 18/21 (85.7%)
Baseline: 0 known expected failures documented in baseline.yml

Core Scenarios

Scenario	Status	Checks
tools_call	PASS	1/1
sse-retry	PASS	3/3
initialize	PASS	1/1
elicitation-sep1034-client-defaults	PASS	5/5

Auth Scenarios

Scenario	Status	Checks	Notes
auth/token-endpoint-auth-post	PASS	20/20
auth/token-endpoint-auth-none	PASS	20/20
auth/token-endpoint-auth-basic	PASS	20/20
auth/scope-step-up	PASS	20/20
auth/scope-retry-limit	PASS	17/17
auth/scope-omitted-when-undefined	PASS	16/16
auth/scope-from-www-authenticate	PASS	16/16
auth/scope-from-scopes-supported	PASS	16/16
auth/resource-mismatch	PASS	3/3	draft (ignored for tier)
auth/pre-registration	PASS	15/15
auth/metadata-var3	PASS	15/15
auth/metadata-var2	PASS	15/15
auth/metadata-var1	PASS	15/15
auth/metadata-default	PASS	15/15
auth/cross-app-access-complete-flow	FAIL	0/2	extension (ignored for tier)
auth/client-credentials-jwt	FAIL	0/1	extension (ignored for tier)
auth/client-credentials-basic	FAIL	0/1	extension (ignored for tier)
auth/basic-cimd	PASS	15/15
auth/2025-03-26-oauth-metadata-backcompat	PASS	13/13
auth/2025-03-26-oauth-endpoint-fallback	PASS	7/7

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Issue Triage Details

Analysis period: Last 42 issues
Labels: needs confirmation, needs repro, ready for work, good first issue, help wanted, P0, P1, P2, P3
Missing: bug, enhancement, question

This is fine, because we use GitHub issue types for those, as allowed by the Tiering proposal. For some reason the tool doesn't detect that.

Metric	Value	T1 Req	T2 Req	Verdict
Compliance rate	97.6%	>= 90%	>= 80%	PASS
Exceeding SLA	0	--	--	--
Open P0s	0	0	0	PASS

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Documentation Coverage

Documentation locations found:

• README.md: Main documentation with examples
• docs/: Detailed feature documentation (server.md, client.md, protocol.md)
• examples/: Extensive example implementations

Feature Documentation Table

One row per feature from references/feature-list.md. Use the exact feature numbers and names from that file.

#	Feature	Documented?	Where	Has Examples?	Verdict
1	Tools - listing	Yes	docs/server.md:247	Yes (2 examples)	PASS
2	Tools - calling	Yes	docs/server.md:255	Yes (2 examples)	PASS
3	Tools - text results	Yes	docs/server.md:290	Yes (1 example)	PASS
4	Tools - image results	Yes	docs/server.md:290	Yes (1 example)	PASS
5	Tools - audio results	Yes	docs/server.md:290	Yes (1 example)	PASS
6	Tools - embedded resources	Yes	docs/server.md:290	Yes (1 example)	PASS
7	Tools - error handling	Yes	docs/server.md:292	Yes (1 example)	PASS
8	Tools - change notifications	Yes	docs/server.md:252	Yes (1 example)	PASS
9	Resources - listing	Yes	docs/server.md:127	Yes (2 examples)	PASS
10	Resources - reading text	Yes	docs/server.md:122	Yes (2 examples)	PASS
11	Resources - reading binary	Yes	docs/server.md:155	Yes (1 example)	PASS
12	Resources - templates	Yes	docs/server.md:117	Yes (1 example)	PASS
13	Resources - template reading	Yes	docs/server.md:125	Yes (1 example)	PASS
14	Resources - subscribing	Yes	docs/server.md:136	Yes (1 example)	PASS
15	Resources - unsubscribing	Yes	docs/server.md:140	Yes (1 example)	PASS
16	Resources - change notifications	Yes	docs/server.md:133	Yes (1 example)	PASS
17	Prompts - listing	Yes	docs/server.md:22	Yes (2 examples)	PASS
18	Prompts - getting simple	Yes	docs/server.md:30	Yes (2 examples)	PASS
19	Prompts - getting with arguments	Yes	docs/server.md:32	Yes (1 example)	PASS
20	Prompts - embedded resources	Yes	docs/server.md:54	Yes (1 example)	PASS
21	Prompts - image content	Yes	docs/server.md:54	Yes (1 example)	PASS
22	Prompts - change notifications	Yes	docs/server.md:27	Yes (1 example)	PASS
23	Sampling - creating messages	Yes	docs/client.md:88	Yes (1 example)	PASS
24	Elicitation - form mode	Yes	docs/client.md:195	Yes (1 example)	PASS
25	Elicitation - URL mode	Yes	docs/client.md:136	Yes (1 example)	PASS
26	Elicitation - schema validation	Yes	docs/client.md:135	Yes (1 example)	PASS
27	Elicitation - default values	Yes	docs/client.md:193	Yes (1 example)	PASS
28	Elicitation - enum values	Yes	docs/client.md:165	Yes (1 example)	PASS
29	Elicitation - complete notification	Yes	docs/client.md:157	Yes (1 example)	PASS
30	Roots - listing	Yes	docs/client.md:26	Yes (1 example)	PASS
31	Roots - change notifications	Yes	docs/client.md:23	Yes (1 example)	PASS
32	Logging - sending log messages	Yes	docs/server.md:483	Yes (1 example)	PASS
33	Logging - setting level	Yes	docs/server.md:478	Yes (1 example)	PASS
34	Completions - resource argument	Yes	docs/server.md:449	Yes (1 example)	PASS
35	Completions - prompt argument	Yes	docs/server.md:447	Yes (1 example)	PASS
36	Ping	Yes	docs/protocol.md:477	Yes (1 example)	PASS
37	Streamable HTTP transport (client)	Yes	docs/protocol.md:176	Yes (1 example)	PASS
38	Streamable HTTP transport (server)	Yes	docs/protocol.md:147	Yes (1 example)	PASS
39	SSE transport - legacy (client)	Yes	docs/protocol.md:136	Yes (1 example)	PASS
40	SSE transport - legacy (server)	Yes	docs/protocol.md:136	Yes (1 example)	PASS
41	stdio transport (client)	Yes	docs/protocol.md:125	Yes (1 example)	PASS
42	stdio transport (server)	Yes	docs/protocol.md:130	Yes (1 example)	PASS
43	Progress notifications	Yes	docs/protocol.md:493	Yes (1 example)	PASS
44	Cancellation	Yes	docs/protocol.md:405	Yes (1 example)	PASS
45	Pagination	Yes	docs/server.md:605	Yes (1 example)	PASS
46	Capability negotiation	Yes	docs/server.md:558	Yes (1 example)	PASS
47	Protocol version negotiation	Yes	README.md:33	Yes (1 example)	PASS
48	JSON Schema 2020-12 support	Yes	docs/server.md:315	Yes (1 example)	PASS
—	Tasks - get (experimental)	No	Not implemented	No	INFO
—	Tasks - result (experimental)	No	Not implemented	No	INFO
—	Tasks - cancel (experimental)	No	Not implemented	No	INFO
—	Tasks - list (experimental)	No	Not implemented	No	INFO
—	Tasks - status notifications (experimental)	No	Not implemented	No	INFO

Summary

Total non-experimental features: 48
PASS (documented with examples): 48/48
PARTIAL (documented, no examples): 0/48
FAIL (not documented): 0/48

Core features documented: 36/36 (100%)
All features documented with examples: 48/48 (100%)

Tier Verdicts

Tier 1 (all non-experimental features documented with examples): PASS

Tier 2 (basic docs covering core features): PASS

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Policy Evaluation

Policy Evaluation Assessment

Repository: modelcontextprotocol/go-sdk

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1. Dependency Update Policy: PASS

File	Exists (CLI)	Content Verdict
DEPENDENCY_POLICY.md	No	N/A
docs/dependency-policy.md	No	N/A
.github/dependabot.yml	Yes	Configured
.github/renovate.json	No	N/A

Verdict: PASS — Automated tooling (.github/dependabot.yml) is configured – for updating GitHub actions.
As for dependencies, we have a "Adding and updating dependencies" section in CONTRIBUTING.md that defines our policy. Generally, we try to update the dependencies after every release.

We also have the Go version support policy documented in README.md, "Version compatibility" section.

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2. Roadmap: PASS

File	Exists (CLI)	Content Verdict
ROADMAP.md	Yes	Substantive
docs/roadmap.md	No	N/A

Verdict:

• Tier 1: PASS — Concrete tracking of SEP-1730, SEP-1577, etc.
• Tier 2: PASS — Plan toward Tier 1 exists.

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3. Versioning Policy: PASS

File	Exists (CLI)	Content Verdict
VERSIONING.md	No	N/A
docs/versioning.md	No	N/A
BREAKING_CHANGES.md	No	N/A
CONTRIBUTING.md (versioning section)	Yes	Not found

Verdict:

Go uses semantic versioning by default: https://go.dev/doc/modules/version-numbers. No additional policies are needed.

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Overall Policy Summary

Policy Area	Tier 1	Tier 2
Dependency Update Policy	PASS	PASS
Roadmap	PASS	PASS
Versioning Policy	PASS	N/A