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

Annotations already mark the operation as read-only and non-destructive; description adds deterministic seeded randomness ('same seed gets the same symbol on the same day') and notes that it 'Returns the symbol with full psychological interpretation,' giving useful behavioral expectations.

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?

Five sentences, each providing distinct value: purpose, seeded randomness behavior, seed guidance, return contents, and use cases. The most critical information is front-loaded, with no filler or redundant explanations.

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 tool with no output schema, the description sufficiently explains the returned data (symbol plus interpretation), the deterministic behavior, and parameter usage. It is complete for an agent to select the tool and understand its output without needing additional context.

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 covers all 3 parameters with descriptions, but the tool description enriches seed semantics by suggesting concrete identifiers (userId, email hash, session token) and explains the date-based default behavior. The compact parameter is not addressed in the description, but the schema already documents it.

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?

Description opens with 'Receive a single dream symbol for daily reflection and subconscious exploration,' clearly specifying the output and use case. It distinguishes from sibling tools by focusing on a single daily symbol with seeded randomness, not on listing, ID lookup, letters, or random generation.

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?

Description identifies target use cases ('dream journal apps, wellness platforms, morning ritual apps, meditation tools') and explains when to provide a seed versus omit it, giving concrete context for daily symbol retrieval. However, it does not explicitly name alternative sibling tools for when not to use this one.

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