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

Goes well beyond the annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false) by disclosing the material effects that do and do not occur: no call is placed, nothing is accepted or assigned, no price changes, no execution rights are granted, and the human must start the call under their own Operations write authority. It also names the return payload (spoken text plus the existing web approval URL), which annotations cannot convey.

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?

Front-loads the gating condition and the core action, then layers scope, return value, and prohibitions with no filler sentences. Some sentences are dense and clause-heavy ('Reuses native current offer, tenant, provider, price and generation checks'), which slightly hurts scanability.

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 two-parameter tool with no output schema, the description covers everything an agent needs: gating condition, mode semantics, what is returned, who acts next, what the tool never does, and the sibling to use instead. Nothing material is left to inference.

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 0%, so the description must carry parameter meaning, and it does for mode: 'default IVR' versus 'mode=clarification for a bounded AI conversation collecting non-binding answers, with no acceptance/assignment'. offerId gets only a light gloss ('an exact offerId'), leaving its format constraints to the schema, which keeps it short of a 5.

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 (prepare) and resource (the existing supplier call) bound to an exact offerId, and explicitly distinguishes itself from get_supplier_call for existing attempts. An agent can tell what it creates and what it does not create without opening the schema.

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 precondition ('only after an explicit request'), a negative routing rule ('existing attempts require get_supplier_call; never repeat an uncertain call'), and a prohibition ('do not submit the web form as the model'). Alternatives and when-not-to-use are both covered.

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