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

Annotations already declare readOnly/idempotent/non-open-world, and the description adds real behavioral context beyond them: days_effective reporting, period-archival 'not found' behavior, nulled fields, and the semantics that LOWER position is better while a positive position_change means the brand slipped.

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-loads the purpose, then organizes the rest into a Views list and an Args list, so scanning is easy. It is fairly long, but nearly every line carries parameter or behavioral meaning; only marginal trimming is possible.

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 an 8-parameter tool with 13% schema coverage and no output schema, the description supplies the missing parameter semantics plus key response-field behavior (days_effective, period block, win_rate/threat_count nulls). Nothing needed to call it correctly appears to be missing.

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 13%, so the description must carry the load and it does: it documents brand_id, view, days (with per-view clamping: overall <=90, prompt-trends 7-90), period (overrides days, overall-only, null win_rate/threat_count), include_volume, tag_ids and limit. Only the schema-documented user_intent is absent. This far exceeds the schema.

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 ('Get competitive ranking data in AI search results') with scope ('across all tracked prompts and AI models'). It does not explicitly contrast itself with nearby siblings like get_visibility_scores or compare_brands, so it stops short of a 5.

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?

Gives clear context ('understanding competitive positioning') and, crucially, tells the agent which view answers a specific question ('prompt-trends ... answers which specific prompts are being lost and since when'). No explicit when-not-to-use guidance or named alternatives, so not a 5.

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