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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false), so the burden is lower. The description adds useful context that it targets only *empty* areas and draws names from the outline, but omits what happens with mismatched/duplicate names, partial fills, or whether the operation is idempotent.

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 tight sentences, verb front-loaded, with the name-linkage mechanism stated first and the outline-reading workflow last. 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 4-param mutation with a nested object and no output schema, the description covers purpose, input key provenance, and workflow start point adequately. Minor gap: no guidance on error/partial-fill behavior, but nothing essential to calling it correctly is missing.

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 100%, so the baseline is 3. The description nonetheless adds real meaning beyond the schema by specifying that `texts` keys must exactly match the stub names surfaced by `napkin_deck_outline` and that markdown bullet syntax is accepted — the schema only says 'Placeholder name → content'.

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 ('Fills') and resource ('a slide's empty layout text areas') with a precise mechanism ('by NAME'). It distinguishes itself from siblings by explicitly tying its input to what `napkin_deck_outline` surfaces, so an agent knows exactly what this does versus napkin_slide_update or napkin_deck_write.

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 an explicit prerequisite sequence: 'Read the outline first to see which stubs a slide still has open,' which routes the agent to the correct sibling. It doesn't state a when-not condition (e.g. what to do if the slide has no open stubs), so it stops short of the top bar.

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