update_plan_section

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

No annotations are provided, so the description carries the full behavioral burden, yet it only implies mutation. It does not say whether the section must already exist, what happens if the heading is absent, whether the rest of the file is preserved, or whether the file is created on demand.

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?

A single short sentence with no wasted words, and the key mechanism is front-loaded. However, the brevity reads as under-specification rather than disciplined concision given the missing behavioral and parameter detail.

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?

A three-parameter file-mutating tool with no annotations, no output schema, and no parameter descriptions needs far more than one sentence. An agent cannot tell from this whether a missing heading is an error, whether the file is created, or what the tool returns.

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% across all three required parameters, so the description must compensate. 'By heading' usefully clarifies that the heading parameter identifies the target section, but project_root and content receive no explanation at all (e.g., is content markdown replacing the whole section or appended?).

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?

The description states a specific verb (Update) and resource (a PLAN.md section), and adds the targeting mechanism ('by heading'), so an agent knows exactly what the operation acts on. It does not, however, differentiate itself from adjacent plan-related siblings such as read_plan, init_plan, or task_sync_md.

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 guidance on when to use this versus read_plan, init_plan, or task_sync_md, and no stated preconditions (must PLAN.md already exist?). Usage is only implied by the name and the word 'Update'.

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