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

Annotations only give readOnlyHint=false, so the description carries real weight and delivers: it discloses the non-propagation rule ('Already-assigned copies are not changed') and the two-phase confirm gate ('previews until confirm: true'). That is exactly the kind of side-effect and execution-semantics context the annotation does not provide.

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?

Three short sentences, front-loaded with the action and the field list, then the side-effect caveat, then the execution gate. No 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?

For a confirm-gated mutation with no output schema, the description covers the essential unknowns: what can change, what does not change, and that nothing executes without confirm. Missing only edge cases such as invalid masterHabitId handling and who is authorized to edit.

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?

With 50% schema description coverage and a nested object of 12 inner properties mostly undocumented, the description partly compensates by naming seven editable fields (name, emoji, description, frequency, target, reminder, active) and by restating confirm semantics. It leaves tracker, category, daysOfWeek and the required masterHabitId unexplained, so it adds value but not full coverage.

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 ('Edit a master habit template') and enumerates the editable fields, which distinguishes it from create_master_habit and from update_habit (client-level habit) by the word 'master'. It never names a sibling explicitly, so an agent must infer the boundary rather than be told it.

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: edit an existing master template, with a preview-then-confirm flow. There is no explicit guidance on when to choose this over update_habit, assign_master_habit, or create_master_habit, and no prerequisites (permissions, ownership) are stated.

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