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

Annotations already declare readOnlyHint, openWorldHint, and destructiveHint, so the safety profile is covered. Beyond that, the description adds real value: it discloses the credit cost and the shape of the output (sequence, total sum, step ratios, golden ratio approximation). It does not mention any limits on count or maxvalue size, which would be useful for a compute tool.

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 sentences, front-loaded with purpose and then output content, with the cost note appended in parentheses. The only waste is the redundant name repetition at the start; otherwise every clause carries information.

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 values are already covered, and the three parameters are fully documented in the schema. The remaining gap is behavioral: all parameters are optional, so an agent has no description of defaults or what happens when no count or maxvalue is provided — a meaningful omission for a tool with an implicit required input.

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%, so the baseline is 3. The description echoes the schema's 'count' and 'maxvalue' semantics and mentions starting 'from any position' (mapping to 'startfrom'), but adds no format, range, or precedence detail beyond what the schema already documents.

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 states a specific verb and resource — computes Fibonacci numbers and sequences — and names the two modes (target count or ceiling value). It is clearly distinguishable from anything else in the sibling list. It loses a point only because the opening repeats the tool name verbatim ('Fibonacci Generator: Fibonacci Generator computes...').

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?

No guidance on when to use this tool versus alternatives, and no guidance on how to choose between 'count' and 'maxvalue' modes or what happens if neither is supplied. The mention of 'based on a target count or ceiling value' implies the two modes but never explains the selection logic.

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