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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds genuinely useful non-annotation context: the output is text for the agent, not the user, plus the contents returned and a Metodic link. The contradictory 'show the session' sentence slightly blurs this.

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-loading is good, but the description contains a visibly truncated duplicate ('facili — every activity's agenda slot, method, step-by-step instructions,') and a closing sentence that repeats and contradicts the opening. These defects mean not every sentence earns its place.

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?

No output schema exists, so the description must describe return values, which it does: agenda slots, methods, step-by-step instructions, facilitator tips, materials, and a Metodic link. Combined with read-only annotations this is largely complete, though the self-contradictory display sentence leaves an ambiguity about intended use.

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 100% and there is a single required parameter (session_id) already documented in the schema. The description adds no syntax, format, or sourcing detail for session_id beyond what the schema provides, so the baseline of 3 applies.

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 (READ) and resource (a session) and explicitly distinguishes itself from the sibling session_one_pager. However, the closing line 'Use this to show a session's runnable detail' muddies the read-vs-display distinction the opening establishes, and a truncated duplicate phrase ('facili — every activity's agenda slot...') weakens an otherwise precise statement.

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 explicit when-to-use ('before answering a follow-up') and names the alternative with its triggering condition ('To SHOW the session to the user, call session_one_pager instead'). This is strong routing guidance, but the final sentence contradicts the stated use case by telling the agent to 'show' with this tool, undercutting the exclusion.

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