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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=false, so the mutation profile is covered elsewhere. The description adds nothing beyond that — it doesn't say what happens if an entry already exists in that time slot, whether the supplement must pre-exist in the stack, or whether validation errors are returned for bad dosages.

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 compact sentence with no filler and the core action front-loaded. It is efficient, though the brevity comes at the cost of substance rather than being optimally sized for an 8-parameter mutation.

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 non-idempotent write tool with 8 parameters, no output schema, and near-empty schema descriptions, the definition is too thin — it doesn't cover required-field relationships, unit handling, or what the caller gets back (e.g., the created entry). The annotations only confirm it is a non-destructive, non-idempotent write.

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 only 13% across 8 parameters. The description mentions the time slot but adds no meaning for planId, supplementId, dosage, dosageUnit, mealRelation, notes, or scheduledTime — notably it never explains that dosage requires a companion dosageUnit or how scheduledTime interacts with the timeSlot enum, which is exactly the kind of gap low schema coverage demands the description fill.

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 ('Add') and resource ('a supplement to a plan's schedule') with the placement ('at a time slot'), which is enough to distinguish it from stackwell_update_schedule_entry and stackwell_remove_schedule_entry by name. It stops short of explicitly naming those siblings or clarifying that this creates rather than alters an existing entry.

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 only implied: the tool is for constructing a plan's schedule. There is no guidance on when to call this versus stackwell_update_schedule_entry, stackwell_log_intake (recording actual consumption), or stackwell_set_supplement_pause, and no preconditions such as the plan needing to exist or be active.

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