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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description goes beyond them by stating 'it reads nothing itself, changes nothing, and is free' and disclosing graceful degradation for clients without a window ('the same report as text') — a real behavioral fact an agent needs. It stops short of explaining rendering failure modes, so not a full 5.

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 sentences, all load-bearing: what it draws, when to call it plus the anti-pattern, and the alternative. The primary instruction and the negative rule are front-loaded before the sibling routing note.

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 5-parameter presentation tool with full schema coverage and no output schema, the description covers purpose, trigger, timing, side-effect profile, and fallback rendering. It does not spell out what the rendered output looks like or how failures surface, but nothing essential to correct invocation 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 description coverage is 100%, so every field (kpis, table, columns, notes, title, subtitle) is already documented with examples and limits in the schema. The description only adds a usage hint that the read's numbers are 'the arguments'; it adds no new field-level meaning. Baseline 3 applies.

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 concrete verb and rendering resource: 'Draws numbers as cards and a sortable table inside the chat.' It explicitly distinguishes itself from the closest sibling by naming performance_dashboard and describing the difference (this one draws what you pass; that one reads the numbers itself and switches periods).

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 the trigger ('whenever the person asks to see, show, list, compare or rank numbers, in any language'), the timing ('right after the read that produced them'), a negative instruction ('Do not write that table by hand'), and the routing rule for the alternative tool. When/when-not/alternative are all present.

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