call_tool

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 effectively describes key behaviors: it returns execution results with timing/metadata, raises specific error types (e.g., 'tool_not_found', 'invalid_arguments'), and handles failure scenarios. However, it doesn't mention rate limits, authentication needs, or side effects like network usage, leaving some gaps for a tool that interacts with external servers.

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 well-structured and front-loaded with the core purpose, followed by details on returns and errors. It avoids unnecessary fluff, but the 'Returns' and 'Raises' sections are somewhat verbose and could be more streamlined. Most sentences earn their place by clarifying behavior, though minor trimming is possible.

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 complexity of executing external tools, the description is reasonably complete: it covers purpose, returns, and error handling. With an output schema present, it doesn't need to detail return values extensively. However, it lacks information on prerequisites (e.g., server connection state) beyond error mentions, and behavioral aspects like idempotency or retries are not addressed, leaving minor gaps.

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 100%, so the schema already documents both parameters ('name' and 'arguments') thoroughly. The description adds minimal value beyond the schema by reiterating that arguments are 'provided' and passed to the tool, but it doesn't explain parameter semantics like format constraints or examples. This meets the baseline of 3 for high schema coverage.

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 ('Execute a tool on the connected MCP server') and distinguishes it from sibling tools like 'list_tools' (which enumerates available tools) or 'connect_to_server' (which establishes connections). It explicitly identifies the resource as 'tools on the MCP server' and the verb as 'execute/call', 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.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage by mentioning prerequisites ('connected MCP server') and failure scenarios like 'not_connected', but it does not explicitly state when to use this tool versus alternatives. For example, it doesn't clarify if this is the primary method for all tool executions or if direct tool calls are preferred when available. The guidelines are contextual but lack explicit alternatives or exclusions.

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