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

Annotations already cover readOnly/openWorld/destructive, so the bar is lower, yet the description still adds real context: 1-credit pricing per action, pagination chaining via clips_media_id/max_id, and that audio_id comes from reel results' audio metadata. It does not mention auth or rate-limit traits, but the operational disclosure 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?

Front-loaded with a one-line summary, then a clean per-action bullet structure with inputs and pricing. Slightly verbose with repeated pricing lines, but every sentence carries actionable information.

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?

With an output schema present, return values need not be restated, and the description covers both actions, their inputs, chaining, and cost. It is complete enough for correct invocation, with only minor room to note result-shape differences between actions.

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%, so the baseline is 3, but the description goes further by explaining where each ID originates (audio_id from audio metadata, clips_media_id from a previous result) and what each enables (continuing the feed vs. paging results). This adds sourcing semantics beyond the schema's terse field notes.

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 a precise resource (Instagram Reels) and splits it into two clearly-stated operations, feed and by_audio, each with a specific verb and scope. It also distinguishes itself from instagram_profile (action=reels), so an agent can route correctly without opening the schema.

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?

Each action states its use case and required inputs, and the feed action explicitly excludes the profile case by pointing to instagram_profile (action=reels). The condition selecting each branch is unambiguous, leaving nothing to inference.

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