Avanza MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It describes the return format (list of periods with fields) and hints at read-only behavior ('Get'), but lacks details on error handling, rate limits, authentication needs, or data freshness. It adds some value but leaves gaps for a tool with no annotation coverage.

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 appropriately sized and front-loaded, with the core purpose stated first, followed by returns details, usage context, and a clear example. Every sentence adds value without redundancy, and the structure is logical and efficient.

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 low complexity (1 parameter, no annotations, but with an output schema), the description is mostly complete. It explains the purpose, parameter semantics, and return structure, though it could benefit from more behavioral details like error cases or data limitations. The output schema likely covers return values, reducing the need for extensive output explanation.

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 description adds meaning beyond the input schema, which has 0% description coverage. It explains that 'instrument_id' is an 'Avanza fund ID from search results', clarifying its source and purpose. Since there is only one parameter, the baseline is 4, and the description compensates well for the schema's lack of documentation.

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 specific action ('Get available fund performance periods with returns') and resource ('fund performance periods'), distinguishing it from siblings like get_fund_info or get_fund_chart by focusing on period-based performance data rather than general information or chart visuals.

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 clear context ('Useful for quick performance overview') and implies usage for performance analysis, but does not explicitly state when to use this tool versus alternatives like get_fund_chart or get_fund_info, nor does it specify exclusions or prerequisites beyond needing an instrument_id.

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