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

Annotations already declare readOnlyHint=false, destructiveHint=true, openWorldHint=true, idempotentHint=false, so the safety profile is largely covered. The description adds that it 'submits a Builder task' (i.e., an async job) and enumerates the modes, but does not disclose what the task produces, whether it is polled, or any auth/limit behavior beyond what annotations state.

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 trigger condition and then the action, with no padding. The keyword list in sentence one is dense but serves an explicit routing purpose.

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 scraper with 100% schema coverage and a full annotation set, the description covers the selection of modes adequately. However, it omits a material part of the workflow — that this submits an asynchronous task whose output must be retrieved via the scraper_task_* siblings — leaving an operational gap.

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 fully documents url, dates, num_of_posts, spider_id, etc., including per-mode URL semantics. The description adds nothing beyond naming the modes already present in the spider_id enum, so baseline 3 is appropriate.

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 (submit a Builder collection task) plus resource (Instagram Reel info), and enumerates the three collection modes it supports (ins_reel_by-url, ins_allreel_by-url, ins_reel_by-listurl). It is clearly readable as 'scrape Instagram Reels', though it does not explicitly distinguish itself from siblings like instagram_profiles or instagram_comment.

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 first sentence gives trigger conditions (Reel-related nouns combined with collect/scrape/fetch/extract verbs), which is useful intent-routing. But it gives no when-not-to-use guidance and does not point to the related task-polling siblings (scraper_task_status/result) that an agent needs after submission, nor explain when to prefer this over instagram_profiles.

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