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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so the safety profile is fully covered by structured data. The description adds the useful fact that this is a pure presentation step over already-prepared inputs (not a data-fetching step), but says nothing about what happens with omitted optional fields or what the rendered output looks like.

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?

Two sentences, front-loaded with the verb and resource, with zero filler. Brevity here is appropriate, though the second sentence is thin given how much remains undocumented.

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 17-parameter rendering tool with 0% schema coverage and no output schema leaves the agent guessing which fields to supply, whether all are optional, and what a 'card' output actually is. The low-risk read-only nature limits the damage, but the description is not complete enough for correct invocation.

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 17 parameters, so the description must carry the load. It names only four of the seventeen (metrics, details, tasks, activity) in prose and gives no format, structure, or requiredness guidance for title, badges, status, eyebrow, customer, warnings, progress_percent, or the *_title fields.

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 ('Renders') and a specific resource ('TrackingTime project summary card'), and enumerates the ingredient inputs (metrics, details, tasks, activity). It is distinguishable from siblings like render_task_list or render_time_summary by the resource named, though it never explicitly contrasts itself with them.

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?

'Use after fetching project data' gives a sequencing precondition, implying get_project / list_project_times should run first, but it names no alternative tool and states no exclusion (e.g. when to choose render_task_list instead). Guidance is implied rather than explicit.

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