p6_critical_path

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

Annotations already establish readOnly/idempotent/non-destructive, and the description goes well beyond them: it discloses pagination via offset/next_offset, ordering rules (total float then start, or float path order), exclusion of LOE and WBS summary activities, the completed-activity filter, and the exact meaning of each counts bucket. This is behavior an agent could not infer from the structured fields.

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?

The breadth of information is earned, but it arrives as a dense run-on paragraph led by a literal listing of return keys rather than the tool's purpose. An agent must read several lines of punctuation-heavy prose to extract the mode rules, which could have been structured as short bullets.

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 correctly carries the burden of explaining the return envelope (total, offset, returned, next_offset, rows, counts, schedule_state, note) and the counting semantics. Combined with the mode and exclusion rules, an agent has enough to call and paginate correctly, though project and limit semantics stay thin.

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?

With only 43% schema description coverage, the description compensates substantially: it defines the semantics of mode values, float_threshold_days (forces total float <= N days, incompatible with longest_path), include_completed, and points to p6_query_activities for field meanings. limit and project remain undocumented beyond their schema stubs, so it is strong but not exhaustive.

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?

Names a specific resource and scope: 'Critical activities of the last P6 schedule run (F9), one page', and enumerates the payload keys returned. It distinguishes itself from the generic sibling p6_query_activities by referencing it only for the shared 'fields' parameter, though it never explicitly contrasts with p6_float_analysis, which is the nearest conceptual sibling.

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 concrete selection conditions for the three modes ('project' follows project setting, 'total_float' uses the hours threshold, 'longest_path' uses P6's driving path flag) and states incompatibilities (float_threshold_days is not used with longest_path). No exclusions or alternatives against sibling tools are offered, but the mode semantics are unusually explicit.

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