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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds one genuinely useful fact: the results come from Pexels, i.e. a third-party stock provider with its own catalogue. It says nothing about pagination, result limits, or licensing.

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?

Four words, front-loaded verb, zero waste. It is efficient rather than padded; the brevity is only a problem because it leaves gaps rather than because it wastes space.

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 simple read-only search this is thin: nothing on query syntax, on how many videos come back, or on whether results are cached/attributable. With no output schema, the description is the only place an agent could learn the shape of the response, and it does not.

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 only 50%: project_id is documented in the schema, but the required 'query' parameter has no description anywhere. The description does not compensate by explaining whether query is free-text keywords, a phrase, or supports filters, which is the single most important thing an agent needs here.

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?

States a specific verb and resource ('Search stock videos') and names the underlying provider (Pexels), so an agent can tell it apart from search_photos and search_icons by the media type alone. It stops short of explicitly contrasting itself with those siblings, but the resource noun does most of the work.

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?

There is no guidance on when to reach for this versus web_search or web_fetch, nor any note that this is an external stock-media library rather than a web crawler. The agent must infer usage entirely from the tool name.

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