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

Annotations already cover readOnly/idempotent/non-destructive. The description adds valuable behavioral detail beyond them: one upstream call cached 12h, the rank-tracking portion is DB-only reads, and the tracked.isTracked:false honesty note. It could say more about rate limits or response shape, but the annotations carry the safety profile and the description adds real operational context.

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 core purpose (live SERP snapshot) then the optional tracked add-on. The parenthetical backtick references are dense but purposeful. Slightly heavy for one paragraph but no wasted sentences.

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?

No output schema, but the description discloses the key output fields (the live SERP snapshot, tracked.history, tracked.isTracked, volatility) sufficiently for an agent to interpret the response. It covers sourcing, caching, and failure/absence semantics. Missing only minor details like exact freshness guarantees beyond the 12h cache.

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 all five parameters are already documented in the schema. The description reinforces that sinceDays only affects tracked.history and is ignored when untracked — useful but the schema already says 'Only meaningful when the keyword is tracked.' Baseline 3 applies when the schema does the heavy lifting.

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 specific verb+resource ('Per-keyword SERP overview: a fresh live SERP snapshot for the keyword') and clearly distinguishes the two modes of output (live SERP plus optional tracked history/volatility). It also names the sibling tools it draws from (get_rank_keyword_history/get_rank_volatility_index), making the relationship explicit.

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?

It explains the semantics of the tracked block: 'tracked.isTracked: false means this keyword is not currently tracked,' giving clear context for when the historical portion applies. However, it doesn't explicitly tell the agent when to prefer this tool over get_rank_keyword_history or a plain SERP fetch — no 'use this when... instead of...' framing.

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