# LaunchDarkly vs Mostly Good Metrics

> LaunchDarkly scores 71.3 (BB) to Mostly Good Metrics's 41.7 (E) for feature flags and experiments. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/launchdarkly-vs-mostly-good-metrics
- Markdown: https://www.anchorterminal.com/compare/launchdarkly-vs-mostly-good-metrics.md (~5,150 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

LaunchDarkly scores 71.3 (BB) on agent readiness against Mostly Good Metrics's 41.7 (E), and leads in every scored category. Both do feature flags and experiments.

- LaunchDarkly: grade BB, 71.3/100, rank #162 of 1486. Markdown https://www.anchorterminal.com/tools/launchdarkly.md · JSON https://www.anchorterminal.com/api/v1/tools/launchdarkly.json
- Mostly Good Metrics: grade E, 41.7/100, rank #1277 of 1486. Markdown https://www.anchorterminal.com/tools/mostly-good-metrics.md · JSON https://www.anchorterminal.com/api/v1/tools/mostly-good-metrics.json
- Best product analytics and experimentation tools for AI agents: https://www.anchorterminal.com/best/product-analytics/index.md
- All 153 product analytics comparisons: https://www.anchorterminal.com/compare/product-analytics/index.md

## Which one, for what

### LaunchDarkly (BB)

Good for: An agent that creates and targets feature flags, runs rollouts and experiments, reads experiment results and cleans up stale flags.

Ahead on:
- Reliability, 74 against 29
- Schema & documentation, 89 against 49
- Agent ergonomics, 69 against 49
- Security & auth, 66 against 33
- Payments & pricing, 40 against 30
- Maintenance & community, 82 against 74
- Transparency & trust, 81 against 45

Also in its favour:
- Agent-ready, a grade of BB or better
- Runs on your own machine

Watch for: The hosted MCP server lists 141 tools, and no tool filter for it was found in the reviewed documentation

### Mostly Good Metrics (E)

Good for: Indie and small-team apps that want simple funnels and retention an agent can query.

Watch for: Public beta run by one developer, with no named legal entity in the terms


## Why the edge

### Reliability: LaunchDarkly +45

- LaunchDarkly (74): Graded on the hosted service with the hosted lines. Statuspage at status.launchdarkly.com with 51 components and incident history (20). Read from the history feed (the host's robots.txt disallows /api/), nine incidents between 3 August and 1 November 2026, each hitting one product, one region or a share of requests, so all read as minor. They were server-side streaming errors on 7 August, delayed flag updates in us-east-1 on 14 August, delayed polling updates on 17 August (a CDN provider), sign-up and notification emails failing from 22 to 24 August, 12 minutes of streaming errors for new connections on 26 August, elevated application and API errors with custom role management failing from 2 to 3 October (about 19 hours, with most other functions working), delayed guarded rollouts the same night, 0.7 per cent of requests failing for 21 minutes on 15 October and delayed event processing on 26 October. The 10 July outage, marked critical, has left the window (20). The API docs describe global, route, token and IP limits and say the numbers are not published. Limit and remaining headers report them at run time (5 of 15). 429s carry reset headers, IP limits carry `Retry-After`, and the docs ask for jitter and backoff. No idempotency keys were found, though JSON patch can test a resource version and 409 is documented as retryable (11 of 15). The SLA commits to 99.9 per cent for Enterprise support and 99.99 per cent for Premium support (10). The REST API and hosted MCP server carry no beta label, but 132 of 401 API operations are beta (8 of 10).
- Mostly Good Metrics (29): Graded on the hosted service with the hosted lines. No status page was found (0) and no incident history could be read (5). Ingestion limits are documented per plan (1,000 to 100,000 events a minute and 10,000 to 1,000,000 an hour), but no limit for MCP or query calls was found (12 of 15). 429 with Retry-After in the header and body, and the SDKs queue events and back off. No idempotency or safe-retry guidance for writes (12 of 15). No SLA (0). The press kit calls the product a public beta (0). 0+5+12+12+0+0 = 29.

### Schema & documentation: LaunchDarkly +40

- LaunchDarkly (89): OpenAPI 3.0.3 served without a login at app.launchdarkly.com/api/v2/openapi.json, with 253 paths and 401 operations (25). The hosted MCP input schemas need a sign-in and were not read. A docs index for agents at launchdarkly.com/docs/llms.txt, and docs pages answer as Markdown with .md (10). 399 of 401 operations have a description. The MCP tool descriptions on the server page average about 740 characters and state pagination, sorting, plan limits and which tool to call next (17). 169 enums across 746 schemas. JSON patch bodies and semantic patch instructions are loosely typed objects (9). 1,853 examples in the spec, 429 documented on 287 operations and 403 on 355, and an error table with a suggested fix for each status (13). Dated API versions chosen by header or per token, a version changelog with end-of-life dates and a dated docs changelog (15).
- Mostly Good Metrics (49): No OpenAPI file was found. The docs say every MCP tool describes its own parameters, and the query definition object is documented in full; we didn't open an MCP session to read the schemas (12 of 25). No llms.txt (404) and no Markdown pages served for agents (0). Each tool area is documented with examples, and the docs say when to use query_metrics instead of repeated execute_query calls (10 of 20). The query definition lists metrics, dimensions, date ranges and filter operators (9 of 15). The ingestion API documents its error body and status codes, and query_metrics reports per-item errors (11 of 15). /v1 and /api/v2 paths and dated SDK tags, but no product changelog (7 of 15). 12+0+10+9+11+7 = 49.

### Transparency & trust: LaunchDarkly +36

- LaunchDarkly (81): Closed hosted service under published terms. The SDKs and `ldcli` are Apache-2.0 and the local MCP server is MIT (17 of 30). The privacy policy (8 April 2025) excludes data processed for customers, which the DPA (1 May 2024) covers, with deletion on written request after termination. The privacy policy gives no retention periods. The terms allow use of anonymised and aggregated data, and no clause on model training was found (20 of 30). The end-of-life policy gives API and SDK versions 12 months after a new release, and the version table lists end-of-life dates. Beta resources may change without notice (17 of 20). The sub-processor list (15 May 2026) gives locations, with Anthropic, OpenAI and Speakeasy under AI services, the DPA gives 30 days' notice of new sub-processors, and EU and federal instances exist (20).
- Mostly Good Metrics (45): The service is closed; the SDKs and CLI are MIT. Terms of December 2025 with no legal entity named (18 of 30). The privacy policy and terms agree on raw-event retention for the subscription's life and deletion within 14 days of account deletion; the about page says data is not used to train models. No DPA was found (18 of 30). The legacy X-MGM-Key header is still supported, and no deprecation policy was found (3 of 20). The terms name eight sub-processors with their purpose, without data locations (12 of 20). 18+18+3+12 = 51.

### Security & auth: LaunchDarkly +33

- LaunchDarkly (66): The hosted MCP server uses OAuth with PKCE (S256), dynamic client registration, a revocation endpoint and three scopes, and an authorised app can never do more than the member who approved it. API access tokens are revocable and resettable with a Reader, Writer, Admin or Owner role. Custom roles and inline policies need a plan with custom roles, and service tokens need Enterprise. No secret in a URL query string is documented (26 of 30). Reader role and reader scope, `--scope read` and `--tool` on the local server, and approval requests for changes on Enterprise. No confirmation step for destructive hosted tools was found (14 of 20). The observability tools return logs, traces, errors and session data written by end users. No prompt-injection guidance was found in the MCP docs, which warn only that an API key in a config file may appear in a conversation (3 of 15). Change history with an API at `/api/v2/auditlog` and comments on updates, limited to 30 days on the Developer plan, and the pricing table lists audit logging under Enterprise only (11 of 15). The security page lists SOC 2 Type II, ISO 27001 and FedRAMP authorisation. security.txt returns 404, and no disclosure policy or bug bounty was found on the pages read (12 of 20).
- Mostly Good Metrics (33): OAuth 2.0 with PKCE, dynamic client registration and a revocation endpoint for MCP and the CLI; project ingest keys in a Bearer header that can be pinned to origins or app IDs. The only tool scope advertised is mcp:tools, so a connection gets every tool the user can use (24 of 30). Restricted keys and a confirmation step for unrestricted keys in the CLI; no read-only MCP mode or approval for deletes was found (6 of 20). Event properties come from apps and end users and reach the agent, and no prompt-injection guidance was found (3 of 15). No audit log was found (0). No security.txt, disclosure policy or certification was found (0). 24+6+3+0+0 = 33.

### Agent ergonomics: LaunchDarkly +20

- LaunchDarkly (69): The hosted MCP server lists 141 tools, far past 30 (5). The OAuth metadata names reader, writer and observability scopes, but no tool filter for the hosted server was found. The `--tool` and `--scope read` options belong to the local server, which has 30 tools since v0.7.2 (27 October 2026), so 3 of 10 added back (8). The API has `limit` and `offset` on 61 operations, filters and sorting, summary and detailed representations and an `expand` parameter on 40 (18). Errors carry `code`, `message` and `id`, with a table of statuses and fixes (15). The server page marks 73 tools read-only, 35 destructive and 89 idempotent. There are no idempotency keys on REST writes, and JSON patch can test a version before applying (15). Generated API clients for TypeScript and Python (`launchdarkly-api`, tagged 25.1.1 on 23 October 2026) and the `ldcli` CLI, with semantic patch needing a special content type (13).
- Mostly Good Metrics (49): 53 tools, more than 30 (5). We added 3 because Goals and Alerts tools load only where enabled and query_metrics batches up to 10 queries (8 of 25). Date ranges, grouping and filters on queries; no documented page or limit parameters for lists (12 of 20). JSON errors with a message, and per-item status in batch results (13 of 20). Annotations weren't readable without a session, the tool list includes deletes and key revocation, and no idempotency keys were found (4 of 20). Five client SDKs and a CLI with `--json` output (12 of 15). 8+12+13+4+12 = 49.

### Payments & pricing: LaunchDarkly +10

- LaunchDarkly (40): No x402, MPP or L402 (0). Per-unit prices are public without a login, at $10 a service connection a month, $8.33 per 1,000 client-side MAU a month billed yearly and $5 per 1,000 additional AI runs. Enterprise is custom (20). The Developer plan is free with no card (20). A person signs up in a browser and approves OAuth or creates a token (0).
- Mostly Good Metrics (30): No x402, MPP or L402 (0). Plan prices with event allowances are on the home page; no per-event price (10). Free plan with no card, stated on the home and about pages (20). Signup and OAuth approval happen in a browser (0). 0+10+20+0 = 30.

## Score by category

| Category | Weight | LaunchDarkly | Mostly Good Metrics | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 74 | 29 | LaunchDarkly +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 49 | LaunchDarkly +40 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 49 | LaunchDarkly +20 |
| Security & auth | 14% (17.5 this run) | 66 | 33 | LaunchDarkly +33 |
| Payments & pricing | 10% (12.5 this run) | 40 | 30 | LaunchDarkly +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 82 | 74 | LaunchDarkly +8 |
| Transparency & trust | 7% (8.8 this run) | 81 | 45 | LaunchDarkly +36 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **71.3 · BB** | **41.7 · E** | |

## Facts side by side

| Fact | LaunchDarkly | Mostly Good Metrics |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Catamorphic, Co. (dba LaunchDarkly) | Mostly Good Metrics |
| Hosted endpoint | `https://mcp.launchdarkly.com/mcp/launchdarkly` | `https://app.mostlygoodmetrics.com/mcp` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under LaunchDarkly's terms. The local MCP server is MIT and the ldcli CLI is Apache-2.0 | none |
| Tools exposed | 141 | 53 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-10-27 | 2026-10-16 |
| Terms last updated | 2025-09-08 | 2025-12-01 |
| Privacy policy last updated | 2025-04-08 | 2025-12-01 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 3.3M npm/wk, 2.2M PyPI/wk | 81 npm/wk |
| Agent reviews | 3.5/5 (4) | none |

## How the scores have moved

### LaunchDarkly

- +2.0 on 1 November 2026 (B to BB): time
- +0.1 on 27 October 2026: checklist

### Mostly Good Metrics

No score change since it was listed.

## Verdicts

**LaunchDarkly.** LaunchDarkly suits agents that manage feature flags, rollouts and experiments. The hosted MCP server uses OAuth with dynamic client registration and marks its tools read-only or destructive, and the Developer plan is free without a card. The server lists 141 tools, numeric rate limits are unpublished, and every REST API version except 20240415 stops working on 31 December 2026.

**Mostly Good Metrics.** Mostly Good Metrics lets an agent run ad-hoc funnels, retention and up to ten metric queries per call through a hosted MCP server with OAuth, at prices from $0. It is a public beta built by one developer, with no status page, no named legal entity and no security policy found.

## Before you call either

### LaunchDarkly

1. Connect to https://mcp.launchdarkly.com/mcp/launchdarkly over streamable HTTP with OAuth. On the EU or federal instance run the local `@launchdarkly/mcp-server` with `--server-url`
2. Authorise with a Reader role or the `reader` scope unless the task writes. A 403 after consent means the member's role lacks access
3. Send `LD-API-Version: 20240415` on every REST call, and `LD-API-Version: beta` for beta resources, which answer 403 without it
4. Read `X-Ratelimit-Global-Remaining`, `X-Ratelimit-Route-Remaining` and `X-Ratelimit-Reset` on each response, and wait `Retry-After` seconds on an IP limit
5. Send `Content-Type: application/json; domain-model=launchdarkly.semanticpatch` for semantic patches, or the body is read as JSON patch and answers 400

### Mostly Good Metrics

1. Use query_metrics for several aggregate questions instead of repeated execute_query calls
2. Pass inline definitions to execute_funnel and execute_retention rather than creating saved objects
3. Confirm with the user before delete, revoke_api_key or stop_experiment calls, since the server doesn't ask
4. Start a fresh agent session after connecting, since a running client may not reload the tool list
5. On 429 from ingestion, wait for Retry-After before resending events

## Questions

### Which is better for AI agents, LaunchDarkly or Mostly Good Metrics?

LaunchDarkly scores 71.3 (BB) on agent readiness against Mostly Good Metrics's 41.7 (E), and leads in every scored category.

### Do LaunchDarkly and Mostly Good Metrics need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call LaunchDarkly and Mostly Good Metrics without installing anything?

Yes. LaunchDarkly has a hosted endpoint at https://mcp.launchdarkly.com/mcp/launchdarkly and Mostly Good Metrics at https://app.mostlygoodmetrics.com/mcp.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/launchdarkly-vs-mostly-good-metrics.json, and with the fewest tokens: https://www.anchorterminal.com/compare/launchdarkly-vs-mostly-good-metrics.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "launchdarkly", "b": "mostly-good-metrics"}`. From a terminal: `anchor compare launchdarkly mostly-good-metrics`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/launchdarkly.json and https://www.anchorterminal.com/api/v1/tools/mostly-good-metrics.json

## Other comparisons with LaunchDarkly or Mostly Good Metrics

- [Amplitude vs Mostly Good Metrics](https://www.anchorterminal.com/compare/amplitude-vs-mostly-good-metrics.md)
- [Basedash MCP vs Mostly Good Metrics](https://www.anchorterminal.com/compare/basedash-mcp-vs-mostly-good-metrics.md)
- [Countly vs Mostly Good Metrics](https://www.anchorterminal.com/compare/countly-vs-mostly-good-metrics.md)
- [Fullstory vs Mostly Good Metrics](https://www.anchorterminal.com/compare/fullstory-vs-mostly-good-metrics.md)
- [Matomo vs Mostly Good Metrics](https://www.anchorterminal.com/compare/matomo-vs-mostly-good-metrics.md)
- [Mixpanel vs Mostly Good Metrics](https://www.anchorterminal.com/compare/mixpanel-vs-mostly-good-metrics.md)
- [Mostly Good Metrics vs OpenPanel](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-openpanel.md)
- [Mostly Good Metrics vs Optimizely Experimentation](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-optimizely.md)
- [Mostly Good Metrics vs Pendo](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-pendo.md)
- [Mostly Good Metrics vs PostHog](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-posthog.md)
- [Mostly Good Metrics vs Statsig](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-statsig.md)
- [Mostly Good Metrics vs Userpilot](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-userpilot.md)
- [Mostly Good Metrics vs Woopra](https://www.anchorterminal.com/compare/mostly-good-metrics-vs-woopra.md)
- [Amplitude vs LaunchDarkly](https://www.anchorterminal.com/compare/amplitude-vs-launchdarkly.md)
- [Countly vs LaunchDarkly](https://www.anchorterminal.com/compare/countly-vs-launchdarkly.md)
- [Flagsmith vs LaunchDarkly](https://www.anchorterminal.com/compare/flagsmith-vs-launchdarkly.md)
- [Harness Feature Management & Experimentation vs LaunchDarkly](https://www.anchorterminal.com/compare/harness-fme-vs-launchdarkly.md)
- [LaunchDarkly vs Mixpanel](https://www.anchorterminal.com/compare/launchdarkly-vs-mixpanel.md)
- [LaunchDarkly vs Optimizely Experimentation](https://www.anchorterminal.com/compare/launchdarkly-vs-optimizely.md)
- [LaunchDarkly vs PostHog](https://www.anchorterminal.com/compare/launchdarkly-vs-posthog.md)
- [LaunchDarkly vs Statsig](https://www.anchorterminal.com/compare/launchdarkly-vs-statsig.md)
- [Heap vs Mostly Good Metrics](https://www.anchorterminal.com/compare/heap-vs-mostly-good-metrics.md)
- [Flagsmith vs Mostly Good Metrics](https://www.anchorterminal.com/compare/flagsmith-vs-mostly-good-metrics.md)
- [GrowthBook vs LaunchDarkly](https://www.anchorterminal.com/compare/growthbook-vs-launchdarkly.md)
- [GrowthBook vs Mostly Good Metrics](https://www.anchorterminal.com/compare/growthbook-vs-mostly-good-metrics.md)
- [Harness Feature Management & Experimentation vs Mostly Good Metrics](https://www.anchorterminal.com/compare/harness-fme-vs-mostly-good-metrics.md)
- [LaunchDarkly vs Matomo](https://www.anchorterminal.com/compare/launchdarkly-vs-matomo.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp