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

Annotations already declare readOnlyHint and destructiveHint, so the safety profile is covered. The description adds that it returns per-letter counts and suggests a use context, but doesn't disclose details like response shape or potential empty results. This is adequate but not rich.

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?

The description is short and front-loaded with the core function. The first sentence is precise; the second gives a practical use case. The third sentence is somewhat redundant with the first, but overall it wastes little space.

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?

This is a simple read-only tool with one optional, well-documented parameter and no output schema. The description fully explains what the tool returns and why it would be used, making it complete for an agent. No significant gaps remain.

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?

The only parameter, compact, is fully described in the schema with its meaning and token savings. The description doesn't mention it, but schema coverage is 100%, so no additional explanation is needed. Baseline 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?

The description clearly states the tool gets the count of dream symbols for each letter A-Z. It distinguishes itself from sibling tools by focusing on letter-based counts rather than symbol details, IDs, or random symbols.

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 description gives a clear use case: building alphabetical dream dictionary navigation for browsing interpretations by letter. It doesn't explicitly mention when not to use it or name alternatives, but the context is sufficient for an agent to decide when this fits.

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