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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds real behavioral context on top: the one-per-target limit, the self-like prohibition, and that take_back reverses the operation. It does not describe failure modes or response behavior, but the added constraints are genuinely beyond the annotations.

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?

A single dense sentence front-loads the action, then appends the reversal mechanism and the two constraints. Every clause carries information; nothing is padded.

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?

With no output schema, the description still covers the action, the undo path, and the key constraints, which is sufficient for a simple toggle-style mutation. It stops short of saying what happens on a duplicate attempt or invalid target, which is a minor gap.

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 all four parameters are documented in the schema itself. The description only restates take_back semantics ('take one back'), adding little beyond the schema's own 'Remove your glimmer instead.' 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 (give a glimmer / a like), and glosses the invented term 'glimmer' so the agent knows it maps to a like. No sibling tool performs likes, so differentiation is trivially satisfied and the scope is unambiguous.

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?

Tells the agent when to give (to a charm or note you liked) and how to undo (take_back: true), plus two hard constraints: one glimmer per charm/note and never your own. It lacks explicit alternatives, but no sibling covers this capability, so there is nothing to route against.

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