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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds useful output-shape context (per-brand row of metrics over a shared window), which exceeds the annotations. However, it does not state permission requirements, behavior on invalid brand IDs, or metric availability limits, so it adds only moderate value.

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 one-line purpose and workflow framing, then uses a clean Args block. It is appropriately sized, though the workflow sentences could be slightly tighter without losing meaning.

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 read-only comparison tool with annotations covering safety and no output schema, the description provides purpose, workflow context, and full param constraints. It is nearly complete; only explicit sibling differentiation (e.g., vs compare_reports) and edge-case behavior are 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 coverage is only 25% (only user_intent is documented in-schema). The description compensates by documenting brand_ids (2-10 required), days (7-365, default 30), and the metrics enum values ('visibility', 'citations', 'actions', default all). It leaves user_intent undocumented, but the schema already covers that parameter's description, so the gap is minor.

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 ('Compare multiple brands side by side') and adds a concrete workflow framing (agency/pitch, prospect vs competitors, two client brands). This distinguishes it from generic report tools, though it does not explicitly name the nearest sibling, compare_reports, or explain how it differs.

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 agency/pitch framing implies when to use it (competitive comparison), but there is no explicit when-not-to-use guidance and no reference to alternatives such as compare_reports or get_competitors. Usage is inferable but not spelled out.

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