Add TAC (Travel Agent Compassion) agentic benchmark to section 9

[darkness8i8]

Adds one entry to section 9 (agent-specific evaluation): TAC (Travel Agent Compassion), an agentic benchmark for implicit animal-welfare awareness in tool-calling agents.

Why it clears the bar:

• Real benchmark with a novel design: the harmful option is always the strongest topical match and the prompt never mentions welfare, so it measures values-under-ambiguity in agentic tool use rather than refusal behavior. No other agent benchmark covers this axis.
• Verifiable, not judgeable: fully programmatic scorer (reads the final purchase_tickets tool call), zero LLM-judge cost. Fits the list's "verifiable beats judgeable" theme.
• Show-your-work: paper at arXiv:2606.18142; reproducible via UK AISI's inspect_evals (already listed in section 5a) as inspect_evals/tac; live per-model results with completion rates shown alongside welfare rates at compassionbench.com.
• Far from saturation: frontier base scores span 17-65%.
• URL verified, entry follows the house format, one change in this PR.

Disclosure: I'm an author of the benchmark.

🤖 Generated with Claude Code