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

With no annotations, the description carries the burden. It explains that the tool lists skills and details the return contents (id, name, category, description, inputs), plus it clarifies that the tool is a starting point and that skills are playbooks. It does not disclose potential pagination, rate limits, or error behavior, but for a simple listing tool, the behavioral transparency is strong.

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 front-loaded with 'START HERE' and clearly structured in four sentences covering purpose, usage, return value, and next step. It is somewhat verbose due to long enumerations of outcomes and use cases, but every sentence contributes value, so it earns a 4 rather than a 5.

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 is complete for a simple tool: it explains what the tool does, when to use it, what it returns, and how to proceed (via get_skill). Since there is no output schema, the description's explicit mention of return fields adequately compensates. The guidance about common goals and playbooks adds rich context.

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 schema description fully covers the only optional parameter 'category' with examples ('sales', 'recruiting', etc.), so schema coverage is 100%. The main description does not add anything about the parameter, but the baseline of 3 applies because the schema does the heavy lifting.

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 that the tool 'Lists the ready-made API Direct skills' and explicitly enumerates what it returns ('each skill's id, name, category, what it does, and its inputs'). It also distinguishes itself from siblings by positioning as the entry point and referencing get_skill for running a skill, 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 provides explicit when-to-use guidance: 'Whenever the user's request looks like lead-gen, competitor/brand monitoring, recruiting, due diligence, deal sourcing or market research, call this FIRST to check for a matching playbook before improvising your own searches.' It names an alternative (improvising searches) and suggests a follow-up action (get_skill), though it does not explicitly state when not to use the tool.

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