Lista/screener de ativos da B3 (ações, FIIs, BDRs) com busca, filtro por tipo/setor e ordenação (ex.: por variação, volume ou market cap).
| Name | Required | Description | Default |
|---|---|---|---|
| type | No | ||
| limit | No | ||
| search | No | ||
| sector | No | ||
| sort_by | No | ||
| sort_order | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the 'screener' behavior (returning multiple assets) but does not disclose additional details like pagination, default limit, or return format. Since annotations are present, the description does not need to repeat safety, but it adds only minimal behavioral context beyond them.
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 a single, front-loaded sentence that efficiently conveys the tool's core purpose and capabilities. Every phrase adds value, and there is no redundancy or filler.
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?
The description covers the main purpose and capabilities but lacks important context such as usage guidelines versus alternatives, the semantics of 'limit', and any indication of return format or result size. Given the tool has 6 parameters and no output schema, this is a moderate gap, making it adequate but incomplete.
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?
Schema description coverage is 0%, so the description must compensate. It explains 'busca' (search), 'filtro por tipo/setor' (type and sector filters), and 'ordenação' (sort) with examples for sort_by (variação, volume, market cap). However, it does not mention the 'limit' parameter or enumerate allowed sort_by values, leaving gaps in parameter semantics.
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 'Lista/screener de ativos da B3' with specific asset types (ações, FIIs, BDRs), establishing a distinct purpose from sibling tools like 'mercado_quote' and 'mercado_search_ticker'. The verb 'Lista/screener' directly conveys the resource and action, making the tool's function immediately clear.
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?
The description implies usage for listing/filtering/sorting B3 assets, but it does not explicitly state when to use this tool versus alternatives like 'mercado_quote' or 'mercado_search_ticker'. There is no 'use this for X, not for Y' guidance, so the context is implied rather than explicit.
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.
Each tool has a clearly distinct purpose: authenticate and connect are separate (login vs status), the mercado_* tools each target a specific asset class or function (crypto, currency, listing, macro, quote, ticker search), and platform tools like marketplace, report_bug, show_version, and toolkit_info are unambiguous. There is no meaningful overlap that would cause an agent to select the wrong tool.
The naming is mixed: financial tools consistently use the 'mercado_' prefix, but platform tools use a variety of conventions—single words (authenticate, connect, marketplace), verb_noun with underscores (report_bug, show_version), and nouns (toolkit_info). While readable, this inconsistency is noticeable and not as uniform as a strong verb_noun pattern.
At 12 tools, the count is within a reasonable range, but roughly half of the tools are platform-management concerns (authenticate, connect, marketplace, report_bug, show_version, toolkit_info) rather than financial data. This makes the set feel heavier and less focused than a pure market-data server, though it's not excessive.
The financial data tools cover a broad range: quotes, screening, crypto, exchange rates, macro indicators, and ticker discovery—sufficient for a Brazilian market data server. Some potential gaps like news or portfolio management are out of scope, and the platform tools add extra utility, leaving no critical missing operations for the core purpose.