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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered structurally. The description adds no behavioral context beyond that — no return shape, no mention of what a 'letter count' result contains. Adequate but not additive.

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?

Two short sentences, front-loaded with the action and immediately followed by the prerequisite pointer. No filler, no restatement of the tool name or title.

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 single-parameter, no-output-schema read tool with full annotation coverage, the description is minimally sufficient. The gap is that 'letter counts' is never unpacked, so an agent cannot anticipate the response content, though it can call the tool correctly.

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 100% — the single 'category' parameter is documented with its valid range (0-43) and bound by minimum/maximum. The description contributes only the cross-reference to get_all_categories for obtaining valid IDs, so the baseline of 3 applies.

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 letter counts for a Grand Exchange category'), which is enough to distinguish it from siblings like get_ge_info or lookup_item. However, 'letter counts' is an unusual, unexplained concept, leaving some ambiguity about what is actually returned.

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?

Explicitly routes the agent to the sibling get_all_categories when it needs valid category IDs, which resolves the main pre-call prerequisite. It does not, however, say when this tool should be preferred over other Grand Exchange siblings for other purposes.

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