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

With no annotations, the description carries the full burden. It discloses confirm-gating (though the schema's confirm param already says this), partial-update behavior, and the pause-via-isActive semantic, which is genuinely useful. It is silent on permissions/authorization, what happens to omitted fields, and whether edits affect compliance history, leaving significant gaps for a mutation tool.

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?

Five terse sentences, each carrying distinct information. The confirm-gate and partial-update rule come first, then enum values, then the isActive pause trick. 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?

For a 12-parameter mutation tool with no annotations and no output schema, the description covers the gate, update semantics, and the ambiguous enum parameters well. It omits guidance on targetCount's relationship to tracker type (e.g. STEPS/COUNTER targets) and reminderTime format, but the schema covers reminderTime.

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 only 17%, so the description must compensate, and it does for the highest-risk params: frequency enum values (DAILY | WEEKLY | SPECIFIC_DAYS), tracker enum values, category as a HabitCategory, and daysOfWeek as 0..6 (Sun..Sat). It leaves name, emoji, description, and targetCount undocumented, so it falls short of 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 client's habit'. An agent can distinguish this from create_habit, list_client_habits, and get_habit_compliance. It stops short of naming any sibling or explicitly ruling out creation/listing, so 4 rather than 5.

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?

Gives clear operational context: confirm-gated, 'Pass habitId plus only the fields to change' establishes partial-update semantics, and 'Set isActive: false to pause a habit without deleting it' routes a pause scenario to this tool instead of deletion. No explicit when-not or named alternative, so not a 5.

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