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

Annotations only declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false. The description adds genuinely novel behavioral context the annotations lack: a 250-credit Tier 5 cost and an explicit instruction to confirm with the user before invoking. It does not describe output size/latency, but the cost disclosure is the key operational trait.

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?

Front-loaded with the purpose sentence, then inputs, then bracketed metadata for group/endpoint/required/cost. Every line carries information; no filler or redundancy.

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?

Given an output schema exists, return format needn't be explained, and the description covers the core intent, required input, cost, and a key default. The only gap is sibling differentiation and fuller parameter coverage for a 7-param tool with a nested chart object.

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 43%, so the description should compensate more than it does. It names most key inputs and adds real semantics not in the schema ('year default = next year', 'use long for full annual report'), but leaves fields and precision unexplained. It adds moderate value over the structured fields.

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: a long-form annual report that combines natal context with the year's major outer-planet transits clustered by month. It is clearly distinct from the monthly/transit/synastry narrative siblings by scope, though it never names the alternative it differs from.

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?

Provides useful invocation guidance ('use long for full annual report') and a strong cost warning ('Heavy — confirm with user before invoking'), which shapes when to call it. However, it never contrasts this tool with the nearby alternatives (monthly narrative, transit narrative, transit_yearly), so selection among siblings is left to inference.

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