Install Jentic One Beta
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the CompSniper Marketplace and Shipping APIs, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fcompsniper.com%2Fcompsniper" | shStep 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fcompsniper.com%2Fcompsniper" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
What an agent can do with CompSniper Marketplace and Shipping APIs.
Search up to three years of eBay sold history by keyword
Pull completed sales and price history from TCGplayer, Poshmark, and Mercari
Return a sold-price summary without the individual listing rows
Estimate US eBay shipping rates for an item
GET STARTED
Submit a batch of trading-card comps and poll its results
Report account quota and purchased-credit usage
Patterns agents use CompSniper Marketplace and Shipping APIs for, with concrete tasks.
★ Agent-Driven Resale Pricing
An AI agent connected through Jentic can price a resale item without a human researching comps: it searches recent eBay sold history for the item and reads the sold-price summary, then recommends a list price grounded in what the item actually sold for. The summary endpoint returns the aggregate price figures without paging through every listing.
Search eBay sold history for 'vintage denim jacket' and get the sold-price summary to recommend a list price
Trading-Card Comps
Card sellers price against recent completed sales, which move quickly. CompSniper returns TCGplayer completed sales and price history for a card, and a batch operation accepts many cards at once and reports progress, so an agent can comp a full inventory of cards in one run.
Look up completed TCGplayer sales and price history for a card by keyword
Cross-Marketplace Price Check
Demand for an item differs by marketplace. CompSniper exposes Poshmark and Mercari sold listings alongside eBay, so an agent can compare realized prices across platforms and decide where an item is worth listing.
Check Poshmark and Mercari sold listings for a product to compare resale demand across marketplaces
Shipping Cost Estimate
A resale price is only profit after shipping. CompSniper's separate shipping-rates product estimates eBay shipping costs for an item under its own quota, so an agent can fold a shipping estimate into a margin calculation before recommending a list price.
Estimate the eBay shipping rate for a two-pound package to a US buyer
20 endpoints — the compsniper api returns resale price data from public marketplaces and quotes us shipping rates.
METHOD
PATH
DESCRIPTION
/v1/research/sold
Search up to 3 years of eBay sold history
/v1/scrape
Search eBay sold or active listings
/v1/summary
Get sold-price intelligence without listing rows
/v1/tcgplayer/sold
TCGplayer completed sales and price history
/v1/poshmark/sold
Scrape Poshmark sold listings
/v1/mercari
Search Mercari sold or active listings
/v1/shipping/rates
Get eBay shipping-rate estimates
/v1/account/usage
Get account quota and purchased-credit usage
/v1/research/sold
Search up to 3 years of eBay sold history
/v1/scrape
Search eBay sold or active listings
/v1/summary
Get sold-price intelligence without listing rows
/v1/tcgplayer/sold
TCGplayer completed sales and price history
/v1/poshmark/sold
Scrape Poshmark sold listings
/v1/mercari
Search Mercari sold or active listings
/v1/shipping/rates
Get eBay shipping-rate estimates
/v1/account/usage
Get account quota and purchased-credit usage
What agents get from Jentic-routed access to this vendor.
Setup
Wiring CompSniper by hand means handling its bearer cs_live_ key, tracking two separate quotas for comps and shipping, and paging keyword searches per marketplace. Through Jentic you install once, import CompSniper from the API Directory, store the key once, and your agent calls it.
Permission scoping
CompSniper takes its keyword and marketplace as query parameters rather than a resource in the URL path, so rules bound which operations your agent may call, not which marketplace. Limit it to the read lookups it needs, such as eBay sold history and sold-price summaries, and leave the shipping-rate and batch operations out unless you add them.
Credential isolation
Your CompSniper key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'search eBay sold prices' or 'estimate a shipping rate', and Jentic returns the matching CompSniper operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Alternatives and complements available in the Jentic catalogue.
Specific to using CompSniper Marketplace and Shipping APIs through Jentic.
What authentication does the CompSniper API use?
The CompSniper API authenticates with a bearer API key sent as an Authorization header, where live keys carry a cs_live_ prefix per its OpenAPI spec. When you call it through Jentic, the key is stored once by your own Jentic One instance and injected at execution time, so it never reaches the agent's prompt or logs.
How much eBay sold history can the CompSniper API return?
The eBay sold-history search returns up to three years of completed sales for a keyword, with startDate, endDate, ebaySite, and sort parameters to narrow the window. The summary operation returns the aggregate sold-price figures for the same search without the individual listing rows.
What are the rate limits for the CompSniper API?
The OpenAPI spec does not define numeric per-second rate limits, but requests draw down an account quota and purchased credits, and the shipping-rates product uses a separate quota. Check your remaining quota with the account usage operation and see the CompSniper documentation at https://compsniper.com for plan limits.
Can I limit what my agent is allowed to do with the CompSniper API?
Yes. CompSniper takes its keyword and marketplace as query parameters rather than a resource in the URL path, so rules bound which operations the agent may call. Write a rule that allows only the sold-history and summary lookups, so the agent can research eBay prices but cannot submit shipping-rate quotes or card-comp batches that draw down a separate quota, and every call it makes is logged.
How do I search eBay sold history with the CompSniper API through Jentic?
Search Jentic with an intent like 'search eBay sold price history', and Jentic returns the sold-history operation at /v1/research/sold with its input schema so your agent passes a keyword and date range. To run it on your own infrastructure, install Jentic One from its GitHub repo.
Is there a CompSniper MCP server?
You don't need an MCP server to give your agent CompSniper. Jentic connects it directly from the API Directory: import the API, store your key once, and your agent calls the sold-history, summary, and shipping operations on demand.
For Agents
Search marketplace sold-price history across eBay, TCGplayer, Poshmark, and Mercari, return sold-price summaries, estimate US shipping rates, and track account quota through CompSniper.
Use for: Search eBay sold history for a keyword, Get the sold-price summary for an item without the listing rows, Find completed TCGplayer card sales and price history, Check Poshmark sold listings for a product
Not supported: Does not handle listing creation, order fulfillment, or payment processing. Use for marketplace sold-price research and US shipping-rate quotes only.
The CompSniper API returns resale price data from public marketplaces and quotes US shipping rates. It searches up to three years of eBay sold history, pulls completed sales and price history from TCGplayer, Poshmark, and Mercari, and returns sold-price summaries without the individual listing rows. A separate shipping-rates product estimates eBay shipping costs under its own quota, and an account usage endpoint reports remaining requests and purchased credits. Authentication uses a bearer API key with a cs_live_ prefix.
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
Base layer of spec validity and structural soundness.
Aggregated quality score from linter diagnostics, weighted by severity.
Percentage of `$ref` references that resolve successfully.
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
Structural correctness score based on schema issues using logarithmic dampening.
Clarity, completeness, and ingestion readiness for developers and tooling.
How richly the API is illustrated with examples.
Percentage of examples that conform to their schemas.
Percentage of operations with complete response definitions (success, client error, server error).
Health of API ingestion, bundling, and resolution within Jentic pipelines.
Semantic breadth, depth, and agent comprehension for AI systems.
Coverage of descriptions across API elements.
Coverage of RFC 9457 Problem Details for error responses.
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
Coverage of summaries across operations/tags/info.
Functional utility, complexity comfort, and AI orchestration readiness.
Agent comfort level based on API operational and structural complexity.
Trust, risk posture, and security compliance.
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
Findability, semantic richness, and reasoning readiness.
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>