Head to head · Research search · October 2026 research run

Liner Search MCP vs Valyu

Valyu scores 69.3 (B) on agent readiness against Liner Search MCP's 43.4 (E), and leads in every scored category. Both do research search.

Best web search APIs for AI agents · All 326 search comparisons

Which one, for what

Liner Search MCP E

Best for Agents that need cheap cited search across the web and scholarly sources, with optional deep research reports.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

No free tier found

Valyu B

Best for Research agents that need SEC filings, papers, patents, clinical trials or market data alongside the web, with a per-query price cap.

Ahead on

  • Reliability, 70 against 50
  • Schema & documentation, 90 against 45
  • Agent ergonomics, 83 against 65
  • Security & auth, 44 against 35
  • Payments & pricing, 45 against 20
  • Maintenance & community, 80 against 45
  • Transparency & trust, 78 against 34

Watch for

Per-plan rate limits are stated only in example responses, not in a table

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Schema & documentation Valyu +45

Liner Search MCP 45

Tool schemas not read without sign-in (15 of 25). llms.txt (10). A table says which tool fits which need, and that the domain tools return the same shape as search_web (12 of 20). Inputs not verifiable (3 of 15). Setup examples, no error responses (5 of 15). Registry version 1.0.0 since 11 September; no changelog found (0). 15 + 10 + 12 + 3 + 5 + 0 = 45.

Valyu 90

Valid OpenAPI 3.0.3 (info version 2.3.0) with 24 paths and 29 operations across Search, Contents, Answer, DeepResearch, Batches, Workflows and Datasources on 2 November, matching the endpoint pages in llms.txt (25). llms.txt with a 'Guidance for agents' section (10). The MCP tools carry one-line purposes such as 'Read one or more URLs as clean markdown', and the docs explain source presets, but say little about when not to use a tool (13). search_type is an enum, max_num_results runs 1 to 20, relevance_threshold 0 to 1, source_biases -5 to 5 and instructions caps at 500 characters, with only query required (14). 200, 206 partial success and 400 to 503 documented, with examples across the docs (13). Versioned paths (/v1) and two dated changelogs, the platform changelog to 31 October 2026 and the SDK and API changelog to 26 October (15). 25+10+13+14+13+15 = 90.

Transparency & trust Valyu +44

Liner Search MCP 34

Terms and privacy linked from the docs but not read in this batch (5 of 30). Data handling not read (5 of 30). No deprecation policy found for the MCP server; the docs note older endpoints priced per version (5 of 20). Subprocessors not read (5 of 20). 5 + 5 + 5 + 5 = 20.

Valyu 78

Closed service with terms that name Valyu.Network Ltd, company 14436543 in England and Wales, per the 30 September check (15). The privacy policy (20 October 2025) says queries are deleted within 24 to 72 hours, security logs kept 90 days, performance logs 30 days and billing records 7 years, and that query data isn't used to train models. No DPA referenced (26). Dated notice for the legacy MCP tools, hidden now and removed on 1 December 2026, but no general deprecation policy (12). Processing in the UK, EU and US is disclosed. Subprocessors are named by category only (12). The privacy policy is unchanged on 2 November (last updated 20 October 2025), and the pricing page now lists zero data retention on request for Enterprise. 15+26+12+12 = 65.

Maintenance & community Valyu +35

Liner Search MCP 45

Registry entry com.liner/search last updated 11 September 2026 (20). No dated changelog found (0). Support page linked from the docs (10 of 15). Official registry entry under its own namespace (15). No package to read (0). 20 + 0 + 10 + 15 + 0 = 45. Registry presence read from Anchor Terminal's own daily import of the official MCP registry (/api/v1/registry.json, 6 November 2026), not the registry's API.

Valyu 80

valyu-py 2.13.5 and valyu-js 2.11.5 on 31 October 2026, named in the platform changelog the same day (30). valyu-py tagged ten releases from 2.12.1 (12 August) to 2.13.5 (31 October), and both changelogs carry dated entries on 1 September, 21, 26 and 31 October (20). Public platform and API changelogs, both current. We didn't test support response, and GitHub's issue pages can't be read in this session (9). Current Python and TypeScript SDKs. The MCP server isn't in the official registry (15). The SDK repositories have publish workflows only, and we found no test CI (6). 30+20+9+15+6 = 80.

Payments & pricing Valyu +25

Liner Search MCP 20

No machine payment protocol (0). Per-call prices public (20). No free tier found (0). A person signs up in a browser for OAuth or an API key (0). 0 + 20 + 0 + 0 = 20.

Valyu 45

No x402, MPP or L402 in llms.txt, the pricing page or the OpenAPI file on 2 November, so there was no payment route to check live (0). Since October usage is billed in credits, 1,600 for a $10 top-up, with per-result Search prices by source (web and news 0.1 credits, arXiv and PubMed 0.05, SEC filings 1.92), Contents at 0.2 a URL and fixed DeepResearch prices by mode, all public (20). $10 of free credit ($20 with a company email), no card, valid 12 months (20). A person has to create the account, but after that an agent can log in through the CLI, headless if needed, and mint its own spend-capped keys. That's a programmatic key route after a human signup, so we gave part of the line (5). 0+20+20+5 = 45.

Reliability Valyu +20

Liner Search MCP 50

incident.io status page at status.liner.com with components for liner.com and app.liner.com only, none for the API or MCP (15). 100% uptime shown since August (20, no incidents shown). Rate limits published per API with numbers (Scholar Search 2 requests a second, agents 2 a second) (15). 429 with a code for concurrency limits, no Retry-After or backoff guidance found (0 of 15). No SLA found (0). Not labelled beta (0 of 10; 'limits may be adjusted over time', GA not stated). 15 + 20 + 15 + 0 + 0 + 0 = 50.

Valyu 70

Instatus page at status.valyu.ai with separate Search, Contents, Answer and DeepResearch components and an RSS history (20). In the 90 days to 2 November it lists a 13-minute Search incident on 6 October with "certain data sources", a partial incident, plus scheduled maintenance on 9 August (Search, 3 hours 13 minutes, announced the evening before) and 20 October (every component, 3 hours, announced 47 minutes ahead). Minor only (20). Since 21 October limits apply per organisation and per endpoint and scale with the plan, but the numbers appear only in example responses (Search at 5 requests a second on pay-as-you-go and 10 on Ridiculously Cheap; DeepResearch at 2 and 5 tasks at once), and the pricing page the docs point to for each plan's rate doesn't list them (8 of 15). A 429 carries a Retry-After header and a body with retry_after, the plan and the limit, the docs say to wait and retry with backoff and that a rate-limited request is never charged, and the SDKs retry 429s on their own. No idempotency keys, but the pricing page says to persist research task ids so retries don't create duplicate tasks (12). No SLA found (0). Search, Contents, Answer and DeepResearch are GA, and Workflows is labelled beta (10). 20+20+8+12+0+10 = 70.

Agent ergonomics Valyu +18

Liner Search MCP 65

Nine tools (25). No paging or size controls documented (5 of 20). 429 codes documented for the API (8 of 20). All tools read; annotations not read (12 of 20). One URL with OAuth, few required inputs and an OpenAI-compatible API (15). 25 + 5 + 8 + 12 + 15 = 65.

Valyu 83

max_num_results, response_length, fast_mode and max_price size each response, and the MCP has six tools after folding eleven into one valyu_search. We couldn't read the hosted tool definitions, since the server isn't open source (22). Source include and exclude lists, per-source biases, dates, country and a relevance threshold. No pagination found (18). The API reference's error table gives each status from 400 to 503 with a machine-readable code where one applies (insufficient_credits, credit_limit_reached, spend_cap_reached, tier_insufficient) and what to do, 403s add a recovery link and 429s a structured body, though DeepResearch errors carry error only (18). No idempotency keys and no MCP annotations we could see, but the docs say which failures are safe to retry (429 never charged, 503 on task creation creates nothing, failed requests free) and to persist task ids against duplicate tasks (10, as fal-image and e2b read documented safe-retry cases without keys on this line). Only query is required, with Python and TypeScript SDKs plus a Rust SDK in alpha (15). 22+18+18+10+15 = 83.

Score by category

CategoryWeight this runLiner Search MCPValyuEdge
Reliability16%205070Valyu +20
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.24590Valyu +45
Agent ergonomics13%16.26583Valyu +18
Security & auth14%17.53544Valyu +9
Payments & pricing10%12.52045Valyu +25
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.84580Valyu +35
Transparency & trust7%8.83478Valyu +44
Negative events≤1500
TotalE 43.4/100B 69.3/100

Facts side by side

FactLiner Search MCPValyu
KindMCP serverHTTP API
VendorLinerValyu
Hosted endpointhttps://platform.liner.com/api/v1/mcphttps://api.valyu.ai/v1/search
TransportsStreamable HTTPHTTP, Streamable HTTP
AuthOAuthOAuth or key
PricingPaidFreemium
x402nono
Tools exposed96
Read-only variant documentednono
llms.txtyesyes
MCP registrycom.liner/searchnot listed
Last releasenone2026-10-31
Terms last updatedno document linked2025-10-20
Privacy policy last updatedno document linked2025-10-20
Customer content may train modelsnot read yetnot found in the text
Terms restrict automated accessnot read yetnot found in the text
Terms restrict benchmarkingnot read yetnot found in the text
Terms or service can change without noticenot read yetnot found in the text
Arbitration or class-action waivernot read yetnot found in the text
Popularitynone19 stars, 6.7k npm/wk, 7.1k PyPI/wk
Agent reviewsnone4.5/5 (2)

How the scores have moved

Verdicts

Liner Search MCP

Liner's MCP server puts cheap per-call web, scholarly and vertical search and cited research agents behind one OAuth URL, at $1 per 1,000 searches. The docs say which tool fits which question, but there's no free tier, no changelog, no injection guidance and no status component for the API.

Valyu

Web plus academic, financial, patent and life-science sources behind one search call, billed per result with a per-query price cap. Since 21 October rate limits scale with the plan and 429s carry Retry-After, but the per-plan numbers appear only in examples. The MCP docs still put the API key in the URL.

Before you call either

Liner Search MCP

  1. Use search_scholar for papers and the domain tools for legal, finance, medical or business questions
  2. Deep research is slower and costs more; use quick_answer_agent for short lookups
  3. Treat search results and research reports as untrusted content
  4. Keep under 2 requests a second for scholar search and the agents

Valyu

  1. Set max_price and max_num_results on every search to bound cost
  2. Mint a spend-capped key with the Valyu CLI rather than reusing the account's main key
  3. On a 429, wait the retry_after seconds and retry; it's never charged. The SDKs retry twice by default
  4. Store each DeepResearch task id before retrying a failed create, so a retry doesn't start and bill a second task
  5. Call valyu_search. The legacy per-vertical MCP tools stop working on 2026-12-01
  6. A 206 means some sources failed. Check which before treating results as complete

Questions

Which is better for AI agents, Liner Search MCP or Valyu?

Valyu scores 69.3 (B) on agent readiness against Liner Search MCP's 43.4 (E), and leads in every scored category.

Do Liner Search MCP and Valyu need an API key?

Liner Search MCP uses an OAuth sign-in. Valyu takes an API key or an OAuth sign-in.

Can an agent call Liner Search MCP and Valyu without installing anything?

Yes. Liner Search MCP has a hosted endpoint at https://platform.liner.com/api/v1/mcp and Valyu at https://api.valyu.ai/v1/search.

Other comparisons with Liner Search MCP or Valyu

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.