Retorna as taxas e os preços de todos os títulos ofertados no Tesouro Direto na última cotação oficial (Tesouro Selic, IPCA+, Prefixado, Renda+, Educa+), com a data da cotação. Fonte: arquivo público do Tesouro Nacional.
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Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of behavioral disclosure. It does reveal the data source ('arquivo público do Tesouro Nacional') and the official-quote scope, which is useful. However, it does not mention response structure, update frequency, units/format of rates, or any caveats about the returned data.
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 stating exactly what is returned, followed by a brief source note. Every part earns its place; there is no fluff, repetition, or unnecessary detail.
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?
For a simple, zero-parameter read-only tool with no output schema, the description adequately explains what is returned: rates, prices, quote date, and eligible bond types. It could be more complete by specifying rate units or output format, but the core information needed to invoke and understand the result is present.
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 zero parameters, so parameter semantics are trivial. The description correctly implies that no input is needed to fetch the latest rates, meeting the baseline for a zero-parameter tool; no additional parameter explanation is required.
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 action ('Retorna'), the resource ('taxas e os preços de todos os títulos ofertados no Tesouro Direto'), and the time scope ('última cotação oficial'). The parenthetical list of bond types and the quote date make the tool's purpose specific and easily distinguishable from sibling calculators and rate-history tools.
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 provides no guidance on when to use this tool versus related tools like calculate_tesouro_selic, calculate_tesouro_prefixado, or get_rates_history. There are no stated conditions, exclusions, or alternatives, so the agent must infer usage from the tool name and content.
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.
Many tools are clearly distinct, but the set contains several near-identical clusters: calculate_dividend_income_goal and calculate_dividend_yield both answer 'how much capital is needed to reach a dividend income target', and calculate_real_salary, calculate_raise_vs_inflation, and calculate_salary_time_value overlap heavily on salary/inflation comparisons. Generic tools like compare_investments and compare_with_cdb also blur the boundary with the many specific yield calculators.
Most tools follow a clear verb_noun snake_case pattern with verbs like calculate_, get_, check_, compare_, and advise_. However, the object language is inconsistent (calculate_ganho_capital_imovel alongside calculate_car_affordability), and can_i_quit_job breaks the command-style pattern with a question.
At 114 tools, the server is extremely over-scoped for an MCP surface; an agent cannot reasonably hold all these options in context. The inclusion of a search_calculator tool to route among the others is a strong signal that the tool set itself needs partitioning.
The surface is very comprehensive for Brazilian personal finance: employment, taxes, investments, debt, real estate, vehicles, small business, insurance, and market-data queries are all covered. A few minor gaps exist, such as no dedicated generic boleto-fine calculator or consolidated investment comparison engine, but no core workflow feels badly stranded.
