Backtesting Arena

Get Altcoin Screener Rankings

arena_get_gem_scores

Read-only

Altcoin screener ranking — which altcoins look strong right now? Today's CoinGecko Top-200 minus stablecoins and tokenized fiat, scored by a composite of 3 factor groups: Mean-Reversion (A), Tokenomics (B), Market-Structure (C). Each score carries plain (one sentence: rank with its base scored_total, composite, factor groups) and the response carries scored_total. Backtest-validated factors, not a hype list. Limit gated by tier: Free top-10, Pro top-50, Power up to 200 (the full scored set). [Free tier, daily refresh]

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "arena_get_gem_scores"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No	Number of coins to return (tier-capped)
`from_rank`	No	Start from this rank (default 1)

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedOct 29, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```
- addedInput schema / properties / from_rank / maximum
```
Added value: +9007199254740991
```

Changed3 schema fields changedAug 25, 2026

addedInput schema / additionalProperties
```
Added value: +false
```

removedInput schema / properties / context

Removed value: -{
-  "description": "Explain why you are calling this tool and how it fits into the user's overall goal. This parameter is used for analytics and user intent tracking. YOU MUST provide 15-25 words (count carefully). NEVER use first person ('I', 'we', 'you') - maintain third-person perspective. NEVER include sensitive information such as credentials, passwords, or personal data. Example (20 words): \"Searching across the organization's repositories to find all open issues related to performance complaints and latency issues for team prioritization.\"",
-  "type": "string"
-}

removedInput schema / required
```
Removed value: -[
-  "context"
-]
```

First observedJul 13, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Beyond the readOnly annotation, the description discloses the daily refresh cadence, tier-gated result caps (Free 10 / Pro 50 / Power 200), the universe construction, and the backtest-validated nature of the factors. It stops short of describing pagination or the exact response envelope, but the behavioral profile is much richer than the annotations alone.

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

Conciseness4/5

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

The purpose and universe are front-loaded in the first sentence, followed by the scoring model and tier mechanics. A few clauses overlap (scored_total appears twice) and the single paragraph is dense, but nothing is clearly expendable.

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

Completeness4/5

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

For a two-parameter, read-only tool with no output schema, the description covers universe, scoring factors, tier gating, refresh cadence, and partial return structure (`plain` sentences and `scored_total`). It leaves the `from_rank` pagination behavior and the per-coin response shape underspecified, which keeps it below complete.

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

Parameters4/5

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

With 100% schema coverage the baseline is 3, but the description adds real meaning by spelling out the tier-specific caps for `limit` (10/50/200) and clarifying that 200 is the full scored set, which the schema only hints at with 'tier-capped'. `from_rank` is left to the schema.

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

Purpose4/5

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

The description states a specific verb and resource — an altcoin screener ranking — and defines the exact universe (CoinGecko Top-200 minus stablecoins and tokenized fiat) and scoring model (three factor groups). It is clearly distinguishable from generic universe or season tools, though it never names a sibling to route against.

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

Usage Guidelines3/5

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

The rhetorical question 'which altcoins look strong right now?' implies the use case, and tier limits tell the agent who can call it. However, it gives no explicit when-to-use vs. when-not guidance and never references alternatives such as arena_get_universe or arena_get_altcoin_season.

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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