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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description adds real value beyond those: output components (Selah rate, guide range, priced add-ons, sourcing link), currency (USD), and no-account-needed. It does not cover latency, caching, or error behavior, so it stops short of a 5.

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 the core question and output contents before examples and exclusions. Slightly long, but every sentence carries information (inputs, examples, prerequisites, exclusions, currency, auth).

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 exists, so the description must describe returns – and it does, enumerating the four output components. Inputs, exclusions, and currency are covered. Minor gap: no guidance on handling audience sizes outside the 100–10M range or usage_months >12, which the schema enforces but the description does not mention.

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 every parameter is already documented in the schema. The description names the required pair and grouped optional concepts (usage rights, exclusivity, rush) at a high level, which is sensible framing but adds no syntax, units, or defaults beyond the schema. 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?

States a specific verb and resource (returns Selah's rate, published-guide range, add-ons, and sourcing link for a sponsored deliverable). It also explicitly excludes adjacent domains (contracts, legal/tax, brand-finding, UGC/affiliate/commission work), which cleanly separates it from selah_check_offer.

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?

Provides concrete example queries ('how much for an Instagram Reel with 50K followers', 'usage rights', 'TikTok at 25K') and states prerequisites (deliverable + audience size) and the failure mode (ask the creator rather than guess). Exclusion list further disambiguates when not to use it.

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