index_historyGet historical Crypto Fear & Greed Index values (most recent first), plus a summary (latest, average, min, max). Each entry has a date, the 0–100 value, and its classification. Keyless.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Number of days of history to return (default 30, max 365). |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "limit": 30
+ },
+ {
+ "limit": 90
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint, which cover safety. The description adds that results are sorted most recent first and includes summary stats, but this is minimal extra context beyond the annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely concise with three short sentences, no redundancy, and front-loads the core purpose.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity (one optional parameter, no output schema), the description covers output structure and behavior. Missing default limit value (though schema mentions default 30) is minor.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema has 100% coverage for the single 'limit' parameter, so the description adds no additional parameter meaning beyond what the schema provides. Baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool retrieves historical Crypto Fear & Greed Index values with summary statistics. The purpose is specific and actionable, but it does not differentiate from the sibling 'current_index' tool.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is provided on when to use this tool versus alternatives like 'current_index'. The description lacks explicit context for usage scenarios or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.