Unstuck

Academic Paper Search

paper_search

Read-onlyIdempotent

Search scholarly papers, articles, books and preprints by topic or title: title, authors, year, journal or venue, DOI, link, type and citation count (metadata only, no abstracts). Use it to find sources or citations for a research question. Data source: Crossref. Price: $0.002 per successful call; failed calls are free. Free to try: a few calls a day without a key.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "query": "<query>"
    },
    "name": "paper_search"
  }
}

Input Schema

Name	Required	Description
`limit`	No	How many papers, default 5, max 10.
`query`	Yes	What to search for, e.g. "microplastics drinking water".
`api_key`	No	Your Unstuck API key, if this connection has none. Leave empty to try free tools or to get a key and payment link.
`from_year`	No	Only works published in or after this year.

Output Schema

Name	Required	Description
`query`	Yes
`source`	Yes
`results`	Yes
`balance_usd`	Yes	Remaining prepaid balance, USD.
`charged_usd`	Yes	Amount charged for this call, USD.
`total_results`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 4, 2026

addedInput schema / properties / api_key

Added value: +{
+  "description": "Your Unstuck API key, if this connection has none. Leave empty to try free tools or to get a key and payment link.",
+  "maxLength": 200,
+  "type": "string"
+}

AddedOct 4, 2026

TDQS

A4.5/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only/idempotent/open-world safety, and the description goes well beyond them: data source (Crossref), metadata-only with no abstracts, pricing ($0.002 per successful call, failures free), and the no-key free tier. These are exactly the operational facts an agent needs before calling.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences: the capability and returned fields come first, then the usage cue, data source and cost. Every clause carries distinct information with no padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return-value detail is unnecessary, and the description covers everything else an agent needs: domain, data source, cost model, free-trial behavior, and the metadata-only limitation. Nothing material is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so limit, from_year and api_key are already documented in the schema. The description adds only that results are metadata-only and searchable by topic or title, which is marginal over the structured fields; baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (search) and resource (scholarly papers, articles, books, preprints) and enumerates exactly what is returned: title, authors, year, venue, DOI, link, type, citation count. This is clearly distinguishable from generic siblings like web_search or read_page.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Use it to find sources or citations for a research question" gives a concrete use context. It does not, however, state when to prefer this over the sibling web_search or note any exclusions, so it stops short of explicit alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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