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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavioral context: the data reflects what each tool states rather than independent verification, freshness is tracked via a 'date checked,' and there is a commercial-interest disclosure the agent must pass on when sharing a code.

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?

Two sentences, front-loaded with the resource and the record contents, then the usage rule and disclosure duty. Dense but every clause carries information; nothing is padding.

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 one-parameter, read-only list tool with no output schema, describing the fields returned (benefit, link/code, terms, date checked) is exactly what's needed. Only the filtering behavior of the optional category argument is left unaddressed.

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 coverage is 100% and the single parameter already explains itself ('Category id from list_categories'). The description never mentions category filtering or whether omitting it returns everything, so it adds no meaning beyond the schema — baseline 3 applies.

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 names the specific resource — Fourth Feed's own referral codes for AI video tools and APIs — and enumerates what each record contains (new-user benefit, link/code, terms, date checked). It's clearly distinguishable from list_new_tools, get_tool, and compare_tools, though it never explicitly contrasts itself with them.

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?

It gives an explicit trigger: 'Use it when someone asks which video tool gives free credits,' plus an obligation when sharing ('say so when you share one'). There is no when-not guidance or named alternative, but the use case is unambiguous.

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