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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered externally. The description does add genuine behavior beyond that by disclosing the has_task=false sentinel and the 'completed-or-partial' state semantics, but it says nothing about ordering guarantees, task object contents, or staleness of the returned record.

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-loaded with the core verb and return semantics, followed by the required-parameter block and example. The 14-value enum list is long but earns its place given 0% schema coverage; there is no filler prose.

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?

With no output schema, the description does the useful work of naming the has_task=false case, but it does not describe the shape of the returned task (status, timestamps, task id) or explain the second parameter. Adequate for invocation, incomplete for interpreting the result.

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 carries the full burden — and it does document the required task_type thoroughly, including all 14 allowed values and a worked example the bare schema lacks. It leaves connection_context (the mctx_v1_ pattern param) entirely unexplained, which is the one remaining gap.

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 (Return), resource (the latest completed-or-partial task), and scope (for one task_type), which distinguishes it from tasks_list and tasks_get_status. It does not explicitly name those siblings, but the 'latest' + 'one task_type' framing is specific enough for an agent to select it correctly.

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?

The example call shows the intended invocation and the enum list constrains valid task_type values, but there is no explicit statement of when to use this over tasks_list, tasks_get_status, or tasks_get_create_detail. The 'Mirror of Meta MCP tasks_latest' note is cross-referential rather than actionable guidance, so usage is implied rather than declared.

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