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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real behavioral detail beyond them: exact match takes priority, falling back to partial substring matches, plus a cost caveat that the endpoint is absent from the public credit manifest.

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 behavioral sentence is front-loaded and the bracketed metadata lines are compact and scannable. The endpoint path line is redundant with the tool name, but nothing is bloated.

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?

An output schema exists, so return-shape explanation is not required, and all three parameters are fully described in the schema. Matching behavior, required input, and cost uncertainty are covered; only sibling routing is 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 100%, so all three parameters are already documented in the schema, including the 'fields' compact-mode path syntax and 'precision' rounding. The description only restates the required 'keyword' and its match semantics, adding little beyond structured data; 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?

States a specific verb and resource: 'Look up a dream symbol by keyword.' That is clearly distinct from the sibling decode/element/theme dream tools, which take different inputs. It stops short of naming those siblings to route the agent, so it lands at 4 rather than 5.

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 only guidance is about matching behavior, not about when to pick this tool over astroway_esoteric_dreams_decode or astroway_esoteric_dreams_by_element_element. No prerequisites, no exclusions, no alternatives are stated.

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