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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuine beyond-annotation context: the change feeds novelty and what_next, and is preserved when the source piece is re-read. It leaves implicit that rewording discards the prior text, but the downstream effects are real added value.

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?

One dense sentence front-loads the verb and then packs the mutation options into parentheticals; every clause carries information. The nested parentheses make it slightly harder to scan than a flatter structure would.

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?

For a 6-param mutation tool with no output schema, the description covers the meaningful parameters, id provenance, the at-least-one rule, and downstream effects. Remaining gaps (profile_id, whether prior text is recoverable) are minor against annotations that already signal destructiveness.

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 0%, so the description must carry parameter meaning, and it does: text='reword it', kind='change its kind', topic_id/topic_label with null and find-or-create semantics. Only profile_id is left unexplained, and its role is inferable from context.

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 ('Change one memory') and enumerates the three exact mutations available: reword via text, change kind, or move topics. It anchors unit_id and topic_id to get_memory, distinguishing it from add_to_memory and delete_memory without needing either schema.

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?

'Send at least one' gives the key precondition, and it names get_memory as the source of unit_id/topic_id, plus the null-vs-label semantics for topic. It stops short of explicitly contrasting with the sibling it displaces (add_to_memory for new units), but the context for when to call it is clear.

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