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

With no annotations provided, the description carries the full burden. It discloses edge cases: null player_url for unusable ids or photo posts before 2026-09-26, and that runs deliver single videos only. It also states the tool is 'Free', which is a cost-related behavioral trait. This is good disclosure beyond the schema.

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, dense sentence that packs in the resource, field list, edge cases, parameter source, and cost. Every clause earns its place, and the most important information (what the tool returns) is front-loaded.

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 tool has an output schema, so return values are covered elsewhere. The description covers the key behavioral edge cases and parameter source. It doesn't mention pagination or rate limits, but for a single-resource fetch with an output schema, the description is largely complete. The only gap is api_key semantics, which is minor.

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 0%, so the description must compensate. It explains that hook_id comes from get_run, which adds meaning to the required parameter. However, it doesn't describe api_key at all, and the description doesn't fully explain the format or constraints of hook_id beyond its source. Baseline 3 is appropriate since the description adds some value but leaves api_key undocumented.

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 states a specific verb and resource: 'One hook with every field' – it retrieves a single hook with all its fields. It distinguishes itself from siblings like get_run and find_hooks by focusing on the hook entity and its fields. However, it doesn't explicitly name a sibling alternative, so it's clear but not fully differentiated.

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: it says hook_id comes from get_run, which tells the agent where to obtain the required parameter. It also notes that runs deliver single videos only, which implies a usage constraint. It doesn't explicitly state when not to use this tool or name alternatives, but the context is reasonably clear.

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