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

Annotations declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the write/non-destructive profile is already covered — no contradiction with 'extend'. However the description adds zero behavioral context beyond that: it doesn't say whether the new deadline must be later than the current one, who may invoke it, whether it is reversible or audited, or whether a task can be extended repeatedly.

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?

At three words there is nothing to trim, but this is under-specification rather than conciseness. Brevity that leaves every behavioral and parameter question unanswered does not earn credit.

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?

This is a mutation tool with no output schema, no parameter documentation, and no stated semantics for the extension itself. For a tool that alters a contractual deadline, the description is entirely inadequate — an agent cannot determine validity constraints, authorization, or effects from it.

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% for both required parameters, so the description carries the full burden of explaining them — and it explains nothing. It does not clarify whether 'deadline' is an absolute ISO timestamp (the format hint is all the schema offers), whether task_id is an internal ID or the task's public identifier, or what happens with past-dated values.

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?

Tautological: description restates name/title.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as request_revision or cancel_task for handling a deadline that can't be met. The only usage signal is inferable from the required parameters (task_id, deadline), which is not explicit guidance.

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