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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing that problems are reported in plain words and 'nothing is dropped silently' (error/partial-result behavior), plus the provenance caveat that the data is game-file data that is 'unconfirmed'. That is genuine behavioral context the annotations do not carry.

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 verb, then a colon list of exactly what is returned and which problems are surfaced. Every clause carries information. It is a single dense sentence, so slightly heavy for a one-parameter tool, but nothing reads as filler.

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 and annotations both exist, so the description is not obligated to explain the return shape, yet it summarizes the decoded contents and the failure modes anyway. With one required parameter at full coverage, an agent has everything needed to call it correctly; the only minor omission is a pointer to the related build/plan tools.

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% and the single parameter is documented, so the baseline is 3. The description earns more by spelling out the concrete shape of a valid code and the accepted link form ('a calculator link carrying one after #plan='), which tells the agent what actually counts as a valid input beyond the schema's generic 'share code, or a link that carries one'.

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 gives a specific verb ('Decodes') and a tightly scoped resource ('Everloot talent share code'), and even pins down the input grammar (EL1-<class>-<spec>-<build>-<payload> or a link with #plan=). That is more than clear. It stops short of a 5 only because it never names or contrasts with the obvious siblings (everloot_plan, talent_tree), so sibling differentiation is inferred from the resource rather than stated.

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?

Usage is implied: you reach for this when you hold a share code or a calculator link. There is no explicit when-to-use, no when-not-to-use, and no named alternative, so an agent must infer the boundary against everloot_plan/talent_tree on its own.

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