broker-rails

market_context

Get real-time quotes and headline news for permitted symbols to assess market conditions before trading.

Instructions

Quotes plus headline text for the allowed symbols.

The headlines are the untrusted-content channel: this is where an injected instruction would arrive in a real deployment (news, filings, social). The tool is read-only by construction, so the worst an injection can do is persuade the model -- and the model cannot reach the order path except through rails that never read this text.

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": "market_context"
  }
}

Input Schema

Name	Required	Description	Default
`symbols`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 13, 2026

TDQS

A4.1/5.0

Behavior5/5

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

Since annotations are absent, the description carries the full burden. It explicitly discloses that headlines are untrusted content, that injection is possible, that the tool is read-only by construction, and that the model cannot reach the order path through this text. This is rich, safety-relevant behavioral context far beyond a generic read-only hint.

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?

The description is two sentences, front-loaded with the core function and followed by high-value security context. Every sentence serves a purpose, with no fluff.

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 simple read-only tool with one parameter and an output schema, the description covers the core functionality and provides critical security context. However, it leaves the parameter semantics and allowed set ambiguous, which slightly detracts from completeness.

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

Parameters2/5

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

The single 'symbols' parameter has zero schema description coverage, and the description only adds 'allowed symbols,' leaving unclear which symbols are allowed or the parameter's semantics (e.g., null behavior, format). The schema itself provides basic type info, but the description does not meaningfully compensate for the coverage gap.

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?

The description clearly states a specific verb-resource combination: 'Quotes plus headline text for the allowed symbols.' This distinguishes it from sibling get_quote (which likely provides only quotes) and other trade tools, making the purpose unambiguous.

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 description implies when to use the tool (when both quotes and headline text are needed), but it does not explicitly compare it to siblings like get_quote or state when not to use it. A clear context is present, but no exclusions or alternatives are named.

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

Deploy Server